Add rate limitation in a SectionDevice

[fchiby]

Hello @perexg,

I created an alsa-ucm configuration to my board i350-evk (mt8365-evk).
Here my configuration files:

mt8365-evk.conf.txt
HiFi.conf.txt

However pulseaudio initialization failed because of hw:mt8365evk,2, this pcm device is connected to jack_mic and Amic.

D: [pulseaudio] alsa-util.c: _buffer_size:4408 ,   _period_size:1102
I: [pulseaudio] pcm_hw.c: SNDRV_PCM_IOCTL_PREPARE failed (-22)
D: [pulseaudio] alsa-util.c: _buffer_size:4408 ,   _period_size:1102
I: [pulseaudio] pcm_hw.c: SNDRV_PCM_IOCTL_PREPARE failed (-22)
D: [pulseaudio] alsa-util.c: _buffer_size:4408 ,   _period_size:1102
I: [pulseaudio] pcm_hw.c: SNDRV_PCM_IOCTL_PREPARE failed (-22)
D: [pulseaudio] alsa-util.c: Set neither period nor buffer size.
I: [pulseaudio] pcm_hw.c: SNDRV_PCM_IOCTL_PREPARE failed (-22)
I: [pulseaudio] alsa-util.c: snd_pcm_hw_params failed: Invalid argument
D: [pulseaudio] alsa-util.c: Trying plug:SLAVE='_ucm0006.hw:mt8365evk,2' with SND_PCM_NO_AUTO_FORMAT ...
I: [pulseaudio] pcm.c: Unknown PCM _ucm0006.hw:mt8365evk,2
I: [pulseaudio] alsa-util.c: Error opening PCM device plug:SLAVE='_ucm0006.hw:mt8365evk,2': No such file or directory
D: [pulseaudio] alsa-mixer.c: Profile set 0xaaab0a13a700, auto_profiles=no, probed=yes, n_mappings=0, n_profiles=0, n_decibel_fixes=0
E: [pulseaudio] module-alsa-card.c: Failed to find a working profile.
E: [pulseaudio] module.c: Failed to load module "module-alsa-card" (argument: "device_id="0" name="platform-sound" card_name="alsa_card.platform-sound" namereg_fail=false tsched=yes fixed_latency_range=no ignore_dB=no deferred_volume=yes use_ucm=yes avoid_resampling=no card_properties="module-udev-detect.discovered=1""): initialization failed.

Whith dmesg I got more details about pulseaudio failure:

[  160.295717] mt8365-afe-pcm 11220000.audio-controller: mt8365_afe_fe_hw_params AWB period = 1102 rate = 44100 channels = 1
[  160.295865] mt8365-afe-pcm 11220000.audio-controller: mt8365_afe_int_adda_prepare 'Capture' rate = 44100
[  160.295881] mt8365-afe-pcm 11220000.audio-controller: ASoC: error at snd_soc_pcm_dai_prepare on INT ADDA: -22
[  160.295891]  MTK Codec: ASoC: soc_pcm_prepare() failed (-22)
[  160.295900]  AWB_FE: ASoC: dpcm_be_dai_prepare() failed (-22)
[  160.295908]  AWB_FE: ASoC: dpcm_fe_dai_prepare() failed (-22)
[  160.296395] mt8365-afe-pcm 11220000.audio-controller: mt8365_afe_fe_hw_params AWB period = 512 rate = 44100 channels = 1
[  160.296543] mt8365-afe-pcm 11220000.audio-controller: mt8365_afe_int_adda_prepare 'Capture' rate = 44100
[  160.296559] mt8365-afe-pcm 11220000.audio-controller: ASoC: error at snd_soc_pcm_dai_prepare on INT ADDA: -22
[  160.296569]  MTK Codec: ASoC: soc_pcm_prepare() failed (-22)
[  160.296577]  AWB_FE: ASoC: dpcm_be_dai_prepare() failed (-22)
[  160.296585]  AWB_FE: ASoC: dpcm_fe_dai_prepare() failed (-22)

When I checked the machine driver, hw:mt8365evk,2 FE (AWB) has 8000_192000, while hw:mt8365evk,2 BE (INT_ADDA) has only [8000, 16000, 32000, 48000] as sample rates.
Actually, the rate limitation is not on afe dai, it's on PMIC. So we prefer to not restrict hw:mt8365evk,2 FE AWB rates.

My question is, is it possible to specify the rate limitation in a SectionDevice ? I checked the alsa-ucm-conf documentation and did not find any section for this :/ alsa-ucm-conf docs

Thanks a bunch !

[perexg]

Why BE params does not limit FE params for ASoC? It breaks the PCM user space API - if something is not supported for the given configuration at RUNTIME, it should not be advertised to the user space. The fixed rate setup in UCM is possible, but I would fix the driver at first.

[fchiby]

This issue is fixed by adding this flag https://elixir.bootlin.com/linux/latest/source/include/sound/soc.h#L738