bcm2708-i2s lacks mmap support #1004

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jimbojr opened this Issue Jun 4, 2015 · 28 comments

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jimbojr commented Jun 4, 2015

If the driver supports mmap then ALSA will do sensible automatic rate and sample size conversion.

The problem (apart from it should support mmap as most drivers seem to) is it isn't obvious to those using I2S based sound cards why a lot of things don't work properly. I've now seen quite a few posts on the R-Pi forums and elsewhere. Just two examples: https://www.hifiberry.com/forums/topic/jackd/ and https://www.raspberrypi.org/forums/viewtopic.php?f=98&t=111982&p=769781#p769781

It would be great to add this if we can.

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HiassofT Jun 4, 2015

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MMAP support was present in the inital version of bcm2708-i2s but shortly afterwards removed in commit 62c05a0.

It's not quite clear to me what the strange issues actually were/are.

Ping @koalo, could you elaborate on this?

Ragnar Jensen provides a Wolfson/Cirrus card kernel build with MMAP support enabled and it seems to be working very well.
http://www.element14.com/community/message/149403/l/re-cirrus-logic-audio-card-working-on-the-raspberry-pi-2#149403

I just did a few tests with my Cirrus kernel build (based on top of rpi-4.0.y) with MMAP enabled and it worked fine, too. With MMAP aplay is able to play back 24bit WAVs which won't work without MMAP support.

This is the patch I used when testing:

--- a/sound/soc/bcm/bcm2708-i2s.c
+++ b/sound/soc/bcm/bcm2708-i2s.c
@@ -875,7 +875,9 @@ static const struct snd_soc_component_driver bcm2708_i2s_component = {
 };

 static const struct snd_pcm_hardware bcm2708_pcm_hardware = {
-       .info                   = SNDRV_PCM_INFO_INTERLEAVED |
+       .info                   = SNDRV_PCM_INFO_MMAP |
+                                 SNDRV_PCM_INFO_MMAP_VALID |
+                                 SNDRV_PCM_INFO_INTERLEAVED |
                                  SNDRV_PCM_INFO_JOINT_DUPLEX,
        .formats                = SNDRV_PCM_FMTBIT_S16_LE |
                                  SNDRV_PCM_FMTBIT_S24_LE |

I think we should do some more testing with the various cards (I only have Wolfson/Cirrus cards here), maybe MMAP works fine with the current kernel tree and it's just a matter of adding back the info flags.

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HiassofT commented Jun 4, 2015

MMAP support was present in the inital version of bcm2708-i2s but shortly afterwards removed in commit 62c05a0.

It's not quite clear to me what the strange issues actually were/are.

Ping @koalo, could you elaborate on this?

Ragnar Jensen provides a Wolfson/Cirrus card kernel build with MMAP support enabled and it seems to be working very well.
http://www.element14.com/community/message/149403/l/re-cirrus-logic-audio-card-working-on-the-raspberry-pi-2#149403

I just did a few tests with my Cirrus kernel build (based on top of rpi-4.0.y) with MMAP enabled and it worked fine, too. With MMAP aplay is able to play back 24bit WAVs which won't work without MMAP support.

This is the patch I used when testing:

--- a/sound/soc/bcm/bcm2708-i2s.c
+++ b/sound/soc/bcm/bcm2708-i2s.c
@@ -875,7 +875,9 @@ static const struct snd_soc_component_driver bcm2708_i2s_component = {
 };

 static const struct snd_pcm_hardware bcm2708_pcm_hardware = {
-       .info                   = SNDRV_PCM_INFO_INTERLEAVED |
+       .info                   = SNDRV_PCM_INFO_MMAP |
+                                 SNDRV_PCM_INFO_MMAP_VALID |
+                                 SNDRV_PCM_INFO_INTERLEAVED |
                                  SNDRV_PCM_INFO_JOINT_DUPLEX,
        .formats                = SNDRV_PCM_FMTBIT_S16_LE |
                                  SNDRV_PCM_FMTBIT_S24_LE |

I think we should do some more testing with the various cards (I only have Wolfson/Cirrus cards here), maybe MMAP works fine with the current kernel tree and it's just a matter of adding back the info flags.

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pelwell Jun 4, 2015

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If that's all it takes, I can add a custom DT property to enable MMAP support and expose it via a dtparam setting.

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pelwell commented Jun 4, 2015

If that's all it takes, I can add a custom DT property to enable MMAP support and expose it via a dtparam setting.

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koalo Jun 4, 2015

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I do not know how exactly MMAP is implemented, but it seems to rely on some kind of advanced memory management of the DMA engine or maybe there is still a bug in the driver itself or ALSA.
Anyway, under some constellations, playing back a file that require MMAP and afterwards recording in 24-bit sometimes result in having a loop of the previously played file in the record instead of the recorded audio signal or no signal at all.
Since I was not able to further debug this issue, I decided to disable MMAP, since don't having a feature is better than to have a feature that results in unreliable behavior.
If you decide to enable it per default, it would be very advisable to test it with a wide range of different files with different formats, recording formats and hardware that does support 24-bit and hardware that does not.

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koalo commented Jun 4, 2015

I do not know how exactly MMAP is implemented, but it seems to rely on some kind of advanced memory management of the DMA engine or maybe there is still a bug in the driver itself or ALSA.
Anyway, under some constellations, playing back a file that require MMAP and afterwards recording in 24-bit sometimes result in having a loop of the previously played file in the record instead of the recorded audio signal or no signal at all.
Since I was not able to further debug this issue, I decided to disable MMAP, since don't having a feature is better than to have a feature that results in unreliable behavior.
If you decide to enable it per default, it would be very advisable to test it with a wide range of different files with different formats, recording formats and hardware that does support 24-bit and hardware that does not.

pelwell added a commit that referenced this issue Jun 5, 2015

bcm2708-i2s: Enable MMAP support via a DT property and overlay
The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004
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I've pushed a commit that makes the MMAP support conditional on a DT property. After rebuilding and copying the kernel, modules and overlays to your SD card, add:

dtoverlay=i2s-mmap

to config.txt.

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pelwell commented Jun 5, 2015

I've pushed a commit that makes the MMAP support conditional on a DT property. After rebuilding and copying the kernel, modules and overlays to your SD card, add:

dtoverlay=i2s-mmap

to config.txt.

popcornmix added a commit to raspberrypi/firmware that referenced this issue Jun 7, 2015

kernel: bcm2708-i2s: Enable MMAP support via a DT property and overlay
See: raspberrypi/linux#1004

firmware: dtoverlay: Make most errors non-fatal

firmware: board_info: Use the boardrev after correction
See: #434

firmware: audioserv: Force volume to full when in passthrough mode
See: raspberrypi/linux#997

popcornmix added a commit to Hexxeh/rpi-firmware that referenced this issue Jun 7, 2015

kernel: bcm2708-i2s: Enable MMAP support via a DT property and overlay
See: raspberrypi/linux#1004

firmware: dtoverlay: Make most errors non-fatal

firmware: board_info: Use the boardrev after correction
See: raspberrypi/firmware#434

firmware: audioserv: Force volume to full when in passthrough mode
See: raspberrypi/linux#997
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pelwell Jun 8, 2015

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The latest firmware (Hexxeh/rpi-firmware@9ad0e75) contains the updated module and overlay. Please try it and comment on your findings.

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pelwell commented Jun 8, 2015

The latest firmware (Hexxeh/rpi-firmware@9ad0e75) contains the updated module and overlay. Please try it and comment on your findings.

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HiassofT Jun 8, 2015

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Thanks a lot for the explanation and the commit!

@pelwell could you include the commit in the 4.0 tree as well?

I did several tests with my Cirrus card and the driver rebased
onto rpi-3.18.y and so far everything went well.

First I played a testfile, tried with different samplerates
and 16/24/32 bit. The (packed) 24bit wavs required MMAP support,
for the others I tried both without MMAP and with forced MMAP
(aplay -M).

Immediately afterwards I recorded an audio file. Tried with 44.1
and 48kHz, 16/24/32 bit and also without and with MMAP (arecord -M).

After recording I played back the recorded file, also sometimes
tried with aplay -M.

I did some 15 play-record-play runs and didn't see any of the
issues koalo wrote about.

The only issue I ran into was playback not starting together with a

bcm2708-dmaengine bcm2708-dmaengine: DMA transfer could not be terminated

entry in dmesg. But I think that's unrelated to MMAP support, I saw
this before without MMAP support too (not sure if it's a bug in
the Cirrus driver or somewhere else).

Contributor

HiassofT commented Jun 8, 2015

Thanks a lot for the explanation and the commit!

@pelwell could you include the commit in the 4.0 tree as well?

I did several tests with my Cirrus card and the driver rebased
onto rpi-3.18.y and so far everything went well.

First I played a testfile, tried with different samplerates
and 16/24/32 bit. The (packed) 24bit wavs required MMAP support,
for the others I tried both without MMAP and with forced MMAP
(aplay -M).

Immediately afterwards I recorded an audio file. Tried with 44.1
and 48kHz, 16/24/32 bit and also without and with MMAP (arecord -M).

After recording I played back the recorded file, also sometimes
tried with aplay -M.

I did some 15 play-record-play runs and didn't see any of the
issues koalo wrote about.

The only issue I ran into was playback not starting together with a

bcm2708-dmaengine bcm2708-dmaengine: DMA transfer could not be terminated

entry in dmesg. But I think that's unrelated to MMAP support, I saw
this before without MMAP support too (not sure if it's a bug in
the Cirrus driver or somewhere else).

pelwell added a commit that referenced this issue Jun 8, 2015

bcm2708-i2s: Enable MMAP support via a DT property and overlay
The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004
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pelwell Jun 8, 2015

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Pushed.

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pelwell commented Jun 8, 2015

Pushed.

anholt pushed a commit to anholt/linux that referenced this issue Jun 18, 2015

BCM2708: Add I2S support to board file
Adds the required initializations for I2S
to the board file of mach-bcm2708.

Signed-off-by: Florian Meier <florian.meier@koalo.de>

bcm2708-i2s: Enable MMAP support via a DT property and overlay

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

popcornmix added a commit that referenced this issue Jun 18, 2015

BCM2708: Add I2S support to board file
Adds the required initializations for I2S
to the board file of mach-bcm2708.

Signed-off-by: Florian Meier <florian.meier@koalo.de>

bcm2708-i2s: Enable MMAP support via a DT property and overlay

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

popcornmix added a commit that referenced this issue Jun 18, 2015

BCM2708: Add I2S support to board file
Adds the required initializations for I2S
to the board file of mach-bcm2708.

Signed-off-by: Florian Meier <florian.meier@koalo.de>

bcm2708-i2s: Enable MMAP support via a DT property and overlay

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

popcornmix added a commit that referenced this issue Jun 22, 2015

BCM2708: Add I2S support to board file
Adds the required initializations for I2S
to the board file of mach-bcm2708.

Signed-off-by: Florian Meier <florian.meier@koalo.de>

bcm2708-i2s: Enable MMAP support via a DT property and overlay

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

popcornmix added a commit that referenced this issue Jun 22, 2015

BCM2708: Add I2S support to board file
Adds the required initializations for I2S
to the board file of mach-bcm2708.

Signed-off-by: Florian Meier <florian.meier@koalo.de>

bcm2708-i2s: Enable MMAP support via a DT property and overlay

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004
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jimbojr Jun 24, 2015

I am still not sure this is 'proper' mmap support but I'll give it a whirl for some test files I have.

I wonder if @martinezjavier (who I believe very kindly added mmap support to the bcm2835 GPU driver) would mind looking over the code to say yes or no whether it looks like it supports mmap properly, or if we need to do more work here...

jimbojr commented Jun 24, 2015

I am still not sure this is 'proper' mmap support but I'll give it a whirl for some test files I have.

I wonder if @martinezjavier (who I believe very kindly added mmap support to the bcm2835 GPU driver) would mind looking over the code to say yes or no whether it looks like it supports mmap properly, or if we need to do more work here...

popcornmix added a commit that referenced this issue Jul 3, 2015

BCM2708: Add I2S support to board file
Adds the required initializations for I2S
to the board file of mach-bcm2708.

Signed-off-by: Florian Meier <florian.meier@koalo.de>

bcm2708-i2s: Enable MMAP support via a DT property and overlay

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

popcornmix added a commit that referenced this issue Jul 13, 2015

BCM2708: Add I2S support to board file
Adds the required initializations for I2S
to the board file of mach-bcm2708.

Signed-off-by: Florian Meier <florian.meier@koalo.de>

bcm2708-i2s: Enable MMAP support via a DT property and overlay

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

popcornmix added a commit that referenced this issue Jul 14, 2015

BCM2708: Add I2S support to board file
Adds the required initializations for I2S
to the board file of mach-bcm2708.

Signed-off-by: Florian Meier <florian.meier@koalo.de>

bcm2708-i2s: Enable MMAP support via a DT property and overlay

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

popcornmix added a commit that referenced this issue Jul 20, 2015

BCM2708: Add I2S support to board file
Adds the required initializations for I2S
to the board file of mach-bcm2708.

Signed-off-by: Florian Meier <florian.meier@koalo.de>

bcm2708-i2s: Enable MMAP support via a DT property and overlay

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

popcornmix added a commit that referenced this issue Jul 24, 2015

BCM2708: Add I2S support to board file
Adds the required initializations for I2S
to the board file of mach-bcm2708.

Signed-off-by: Florian Meier <florian.meier@koalo.de>

bcm2708-i2s: Enable MMAP support via a DT property and overlay

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

popcornmix added a commit that referenced this issue Jul 27, 2015

BCM2708: Add I2S support to board file
Adds the required initializations for I2S
to the board file of mach-bcm2708.

Signed-off-by: Florian Meier <florian.meier@koalo.de>

bcm2708-i2s: Enable MMAP support via a DT property and overlay

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004
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BBUK Aug 3, 2015

Thanks for this. I want to use a Hifiberry Amp+ to run two independent mono streams for a multi room solution (one mapped to the left output and one to the right output).

The easiest route to do this is via the alsa dmix plugin which (I understand) needs MMAP.

The i2s-mmap overlay has enabled proper use of dmix and is confirmed working fine for my use case on a RPi B+ (running mpd).

Let me know if you would like me to assist by undertaking any further tests.

Thanks again

BBUK commented Aug 3, 2015

Thanks for this. I want to use a Hifiberry Amp+ to run two independent mono streams for a multi room solution (one mapped to the left output and one to the right output).

The easiest route to do this is via the alsa dmix plugin which (I understand) needs MMAP.

The i2s-mmap overlay has enabled proper use of dmix and is confirmed working fine for my use case on a RPi B+ (running mpd).

Let me know if you would like me to assist by undertaking any further tests.

Thanks again

popcornmix added a commit that referenced this issue Aug 4, 2015

BCM2708: Add I2S support to board file
Adds the required initializations for I2S
to the board file of mach-bcm2708.

Signed-off-by: Florian Meier <florian.meier@koalo.de>

bcm2708-i2s: Enable MMAP support via a DT property and overlay

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

popcornmix added a commit that referenced this issue Aug 5, 2015

BCM2708: Add I2S support to board file
Adds the required initializations for I2S
to the board file of mach-bcm2708.

Signed-off-by: Florian Meier <florian.meier@koalo.de>

bcm2708-i2s: Enable MMAP support via a DT property and overlay

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004
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pelwell Aug 10, 2015

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@BBUK Thanks for the feedback. Unless we reopen the original problem of why enabling MMAP support by default is problematic, I can't think of anything else for you to test.

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pelwell commented Aug 10, 2015

@BBUK Thanks for the feedback. Unless we reopen the original problem of why enabling MMAP support by default is problematic, I can't think of anything else for you to test.

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iqaudio Aug 17, 2015

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@BBUK Can you post details of dmix usage so we can replicate please? I'd like to check this on our boards too.

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iqaudio commented Aug 17, 2015

@BBUK Can you post details of dmix usage so we can replicate please? I'd like to check this on our boards too.

popcornmix added a commit that referenced this issue Aug 17, 2015

BCM2708: Add I2S support to board file
Adds the required initializations for I2S
to the board file of mach-bcm2708.

Signed-off-by: Florian Meier <florian.meier@koalo.de>

bcm2708-i2s: Enable MMAP support via a DT property and overlay

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

popcornmix added a commit that referenced this issue Aug 20, 2015

BCM2708: Add I2S support to board file
Adds the required initializations for I2S
to the board file of mach-bcm2708.

Signed-off-by: Florian Meier <florian.meier@koalo.de>

bcm2708-i2s: Enable MMAP support via a DT property and overlay

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004
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BBUK Aug 23, 2015

@iqaudio No magic really:

config.txt

dtoverlay=i2s-mmap
dtoverlay=hifiberry-amp

asound.conf (I blacklisted the onboard audio driver hence hw:0)

pcm.onboard {
type hw
card 0
}

pcm.!default {
type plug
slave.pcm "onboard_dmix"
}

pcm.onboard_dmix {
type dmix
ipc_key 1024
ipc_key_add_uid 1
ipc_perm 0666
slave {
pcm "onboard"
channels 2
}
bindings {
0 0
1 1
}
}

pcm.zone1 {
type plug
slave.pcm onboard_dmix
slave.channels 2
ttable {
0.0 0.5
1.0 0.5
0.1 0
1.1 0
}
}

pcm.zone2 {
type plug
slave.pcm onboard_dmix
slave.channels 2
ttable {
0.0 0
1.0 0
0.1 0.5
1.1 0.5
}
}

I then set up two instances of mpd with different config files. One outputting to zone1 and one to zone2. So the mpd.conf for zone 1 output would say:

...
audio_output {
type "alsa"
name "Zone1"
device "zone1"
mixer_type "software"
}
...

HTH, BBUK

BBUK commented Aug 23, 2015

@iqaudio No magic really:

config.txt

dtoverlay=i2s-mmap
dtoverlay=hifiberry-amp

asound.conf (I blacklisted the onboard audio driver hence hw:0)

pcm.onboard {
type hw
card 0
}

pcm.!default {
type plug
slave.pcm "onboard_dmix"
}

pcm.onboard_dmix {
type dmix
ipc_key 1024
ipc_key_add_uid 1
ipc_perm 0666
slave {
pcm "onboard"
channels 2
}
bindings {
0 0
1 1
}
}

pcm.zone1 {
type plug
slave.pcm onboard_dmix
slave.channels 2
ttable {
0.0 0.5
1.0 0.5
0.1 0
1.1 0
}
}

pcm.zone2 {
type plug
slave.pcm onboard_dmix
slave.channels 2
ttable {
0.0 0
1.0 0
0.1 0.5
1.1 0.5
}
}

I then set up two instances of mpd with different config files. One outputting to zone1 and one to zone2. So the mpd.conf for zone 1 output would say:

...
audio_output {
type "alsa"
name "Zone1"
device "zone1"
mixer_type "software"
}
...

HTH, BBUK

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Thanks, useful to see a working config.

Best regards,

Gordon

Sent from my iPhone

On 23 Aug 2015, at 15:36, BBUK notifications@github.com wrote:

@iqaudio No magic really:

config.txt

dtoverlay=i2s-mmap
dtoverlay=hifiberry-amp

asound.conf (I blacklisted the onboard audio driver hence hw:0)

pcm.onboard {
type hw
card 0
}

pcm.!default {
type plug
slave.pcm "onboard_dmix"
}

pcm.onboard_dmix {
type dmix
ipc_key 1024
ipc_key_add_uid 1
ipc_perm 0666
slave {
pcm "onboard"
channels 2
}
bindings {
0 0
1 1
}
}

pcm.zone1 {
type plug
slave.pcm onboard_dmix
slave.channels 2
ttable {
0.0 0.5
1.0 0.5
0.1 0
1.1 0
}
}

pcm.zone2 {
type plug
slave.pcm onboard_dmix
slave.channels 2
ttable {
0.0 0
1.0 0
0.1 0.5
1.1 0.5
}
}

I then set up two instances of mpd with different config files. One outputting to zone1 and one to zone2. So the mpd.conf for zone 1 output would say:

...
audio_output {
type "alsa"
name "Zone1"
device "zone1"
mixer_type "software"
}
...

HTH, BBUK


Reply to this email directly or view it on GitHub.

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iqaudio commented Aug 23, 2015

Thanks, useful to see a working config.

Best regards,

Gordon

Sent from my iPhone

On 23 Aug 2015, at 15:36, BBUK notifications@github.com wrote:

@iqaudio No magic really:

config.txt

dtoverlay=i2s-mmap
dtoverlay=hifiberry-amp

asound.conf (I blacklisted the onboard audio driver hence hw:0)

pcm.onboard {
type hw
card 0
}

pcm.!default {
type plug
slave.pcm "onboard_dmix"
}

pcm.onboard_dmix {
type dmix
ipc_key 1024
ipc_key_add_uid 1
ipc_perm 0666
slave {
pcm "onboard"
channels 2
}
bindings {
0 0
1 1
}
}

pcm.zone1 {
type plug
slave.pcm onboard_dmix
slave.channels 2
ttable {
0.0 0.5
1.0 0.5
0.1 0
1.1 0
}
}

pcm.zone2 {
type plug
slave.pcm onboard_dmix
slave.channels 2
ttable {
0.0 0
1.0 0
0.1 0.5
1.1 0.5
}
}

I then set up two instances of mpd with different config files. One outputting to zone1 and one to zone2. So the mpd.conf for zone 1 output would say:

...
audio_output {
type "alsa"
name "Zone1"
device "zone1"
mixer_type "software"
}
...

HTH, BBUK


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pelwell Aug 23, 2015

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Thanks for sharing. Just for the record, with recent firmware (rpi-update, and the forthcoming new Raspbian image) there should be no need to blacklist the snd-bcm2835 driver - just make sure it isn't in /etc/modules and that you don't have dtparam=audio=on. Unlike in older firmware, the inbuilt audio is off unless asked for, but clean Raspbian installs will still include dtparam=audio=on by default.

Contributor

pelwell commented Aug 23, 2015

Thanks for sharing. Just for the record, with recent firmware (rpi-update, and the forthcoming new Raspbian image) there should be no need to blacklist the snd-bcm2835 driver - just make sure it isn't in /etc/modules and that you don't have dtparam=audio=on. Unlike in older firmware, the inbuilt audio is off unless asked for, but clean Raspbian installs will still include dtparam=audio=on by default.

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Just noticed that if dtparam=audio=on is commented out then alsamixer doesn't work (mplayer still plays audio)

Alsamixer error message: "Cannot open mixer: No such file or directory"

If dtparam=audio=on is listed in config.txt then alsamixer works and shows additional i2s audio cards.

Any clues?

G

Sent from my iPhone

On 23 Aug 2015, at 15:59, Phil Elwell notifications@github.com wrote:

Thanks for sharing. Just for the record, with recent firmware (rpi-update, and the forthcoming new Raspbian image) there should be no need to blacklist the snd-bcm2835 driver - just make sure it isn't in /etc/modules and that you don't have dtparam=audio=on. Unlike in older firmware, the inbuilt audio is off unless asked for, but clean Raspbian installs will still include dtparam=audio=on by default.


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iqaudio commented Aug 23, 2015

Just noticed that if dtparam=audio=on is commented out then alsamixer doesn't work (mplayer still plays audio)

Alsamixer error message: "Cannot open mixer: No such file or directory"

If dtparam=audio=on is listed in config.txt then alsamixer works and shows additional i2s audio cards.

Any clues?

G

Sent from my iPhone

On 23 Aug 2015, at 15:59, Phil Elwell notifications@github.com wrote:

Thanks for sharing. Just for the record, with recent firmware (rpi-update, and the forthcoming new Raspbian image) there should be no need to blacklist the snd-bcm2835 driver - just make sure it isn't in /etc/modules and that you don't have dtparam=audio=on. Unlike in older firmware, the inbuilt audio is off unless asked for, but clean Raspbian installs will still include dtparam=audio=on by default.


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What is in your ~/.asoundrc? A quick search suggests that it may have a reference to card 1 when you no longer have one. Try deleting/renaming it and see if that fixes it.

Contributor

pelwell commented Aug 23, 2015

What is in your ~/.asoundrc? A quick search suggests that it may have a reference to card 1 when you no longer have one. Try deleting/renaming it and see if that fixes it.

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Yep, that's it. Thanks Phil.

Gordon

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On 23 Aug 2015, at 16:39, Phil Elwell notifications@github.com wrote:

What is in your ~/.asoundrc? A quick search suggests that it may have a reference to card 1 when you no longer have one. Try deleting/renaming it and see if that fixes it.


Reply to this email directly or view it on GitHub.

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iqaudio commented Aug 23, 2015

Yep, that's it. Thanks Phil.

Gordon

Sent from my iPhone

On 23 Aug 2015, at 16:39, Phil Elwell notifications@github.com wrote:

What is in your ~/.asoundrc? A quick search suggests that it may have a reference to card 1 when you no longer have one. Try deleting/renaming it and see if that fixes it.


Reply to this email directly or view it on GitHub.

popcornmix added a commit that referenced this issue Sep 2, 2015

BCM2708: Add I2S support to board file
Adds the required initializations for I2S
to the board file of mach-bcm2708.

Signed-off-by: Florian Meier <florian.meier@koalo.de>

bcm2708-i2s: Enable MMAP support via a DT property and overlay

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

popcornmix added a commit that referenced this issue Sep 14, 2015

BCM2708: Add I2S support to board file
Adds the required initializations for I2S
to the board file of mach-bcm2708.

Signed-off-by: Florian Meier <florian.meier@koalo.de>

bcm2708-i2s: Enable MMAP support via a DT property and overlay

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

popcornmix added a commit that referenced this issue Sep 14, 2015

BCM2708: Add I2S support to board file
Adds the required initializations for I2S
to the board file of mach-bcm2708.

Signed-off-by: Florian Meier <florian.meier@koalo.de>

bcm2708-i2s: Enable MMAP support via a DT property and overlay

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

popcornmix added a commit that referenced this issue Sep 22, 2015

BCM2708: Add I2S support to board file
Adds the required initializations for I2S
to the board file of mach-bcm2708.

Signed-off-by: Florian Meier <florian.meier@koalo.de>

bcm2708-i2s: Enable MMAP support via a DT property and overlay

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

popcornmix added a commit that referenced this issue Jun 1, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Jun 1, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Jun 1, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Jun 3, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Jun 3, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Jun 3, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Jun 6, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Jun 8, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Jun 8, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Jun 13, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Jun 13, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Jun 21, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Jun 21, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Jun 26, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Jun 26, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Jun 28, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Jul 4, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Jul 12, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Jul 12, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Jul 25, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Jul 25, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Jul 25, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Jul 28, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Aug 9, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Aug 9, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Aug 12, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Aug 19, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Aug 19, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Aug 23, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Aug 23, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Sep 5, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

popcornmix added a commit that referenced this issue Sep 7, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

angyalp added a commit to angyalp/kernel_rpi that referenced this issue Dec 19, 2016

bcm2835-i2s: Enable MMAP support via a DT property
Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829f ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>

neuschaefer pushed a commit to neuschaefer/raspi-binary-firmware that referenced this issue Feb 27, 2017

kernel: bcm2708-i2s: Enable MMAP support via a DT property and overlay
See: raspberrypi/linux#1004

firmware: dtoverlay: Make most errors non-fatal

firmware: board_info: Use the boardrev after correction
See: raspberrypi#434

firmware: audioserv: Force volume to full when in passthrough mode
See: raspberrypi/linux#997
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agherzan Apr 25, 2017

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@popcornmix Any idea why this overlay (i2s-mmap) is not available anymore in 4.9?

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agherzan commented Apr 25, 2017

@popcornmix Any idea why this overlay (i2s-mmap) is not available anymore in 4.9?

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HiassofT commented Apr 25, 2017

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Sounds good. Do you have any idea where is this enabled now in the source?

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agherzan commented Apr 25, 2017

Sounds good. Do you have any idea where is this enabled now in the source?

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HiassofT commented Apr 25, 2017

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Thanks @HiassofT . That makes sense.

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agherzan commented May 1, 2017

Thanks @HiassofT . That makes sense.

@P33M P33M closed this May 17, 2017

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