DisplayLink driver and module #18041

abbradar · 2016-08-27T17:00:19Z

Motivation for this change

Things done

Tested using sandboxing
(nix.useChroot on NixOS,
or option build-use-chroot in nix.conf
on non-NixOS)
Built on platform(s)
- NixOS
- OS X
- Linux
Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
Tested execution of all binary files (usually in ./result/bin/)
Fits CONTRIBUTING.md.

cc @chris-martin for testing. I don't have the necessary hardware so I've just packaged the driver and made a module closely following Arch's AUR package. To enable this:

  services.xserver.videoDrivers = [ "displaylink" ];

mention-bot · 2016-08-27T17:00:29Z

@abbradar, thanks for your PR! By analyzing the annotation information on this pull request, we identified @edolstra, @bjornfor and @offlinehacker to be potential reviewers

chris-martin · 2016-08-27T18:50:14Z

Tested by cherry-picking onto nixos-16.03. Gnome still isn't recognizing an external display.

Journalctl output when connecting a monitor:

Aug 27 14:48:31 renzo kernel: evdi: [D] evdi_painter_connect:433 (dev=-1) Connected with           (null)
Aug 27 14:48:31 renzo kernel: evdi: [D] evdi_detect:69 (dev=1) Painter is connected
Aug 27 14:48:31 renzo kernel: evdi: [D] evdi_detect:69 (dev=1) Painter is connected
Aug 27 14:48:31 renzo kernel: evdi: [D] evdi_painter_get_edid_copy:186 (dev=1) 00 ff ff

Then after unplugging:

Aug 27 14:49:38 renzo kernel: evdi: [D] evdi_painter_disconnect:483 (dev=1) Disconnected from ffff880037728a00
Aug 27 14:49:38 renzo kernel: evdi: [D] evdi_detect:72 Painter is disconnected
Aug 27 14:49:38 renzo kernel: evdi: [W] evdi_painter_disconnect:462 (dev=-1) An unknown connection to ffff880037728a00 tries to close us
Aug 27 14:49:38 renzo kernel: evdi: [W] evdi_painter_disconnect:463  - ignoring
Aug 27 14:49:38 renzo kernel: evdi: [D] evdi_detect:72 Painter is disconnected

abbradar · 2016-08-27T18:51:04Z

Have you tried xrandr magic as described on ArchWiki?

chris-martin · 2016-08-27T19:00:04Z

It doesn't seem that displaylink is being seen as a provider. The --listproviders output hasn't changed.

chris@renzo ~> xrandr --listproviders
Providers: number : 2
Provider 0: id: 0x47 cap: 0x2, Sink Output crtcs: 3 outputs: 5 associated providers: 0 name:modesetting
Provider 1: id: 0x2b0 cap: 0x2, Sink Output crtcs: 1 outputs: 1 associated providers: 0 name:modesetting

chris@renzo ~> xrandr --current
Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 8192 x 8192
eDP-0 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 294mm x 165mm
   1920x1080     59.93*+
   1400x1050     59.98  
   1280x1024     60.02  
   1280x960      60.00  
   1024x768      60.04    60.00  
   960x720       60.00  
   928x696       60.05  
   896x672       60.01  
   800x600       60.00    60.32    56.25  
   700x525       59.98  
   640x512       60.02  
   640x480       60.00    59.94  
   512x384       60.00  
   400x300       60.32    56.34  
   320x240       60.05  
DisplayPort-0 disconnected (normal left inverted right x axis y axis)
HDMI-0 disconnected (normal left inverted right x axis y axis)
DisplayPort-1 disconnected (normal left inverted right x axis y axis)
HDMI-1 disconnected (normal left inverted right x axis y axis)

chris@renzo ~> xrandr --setprovideroutputsource 1 0
X Error of failed request:  BadValue (integer parameter out of range for operation)
  Major opcode of failed request:  140 (RANDR)
  Minor opcode of failed request:  35 (RRSetProviderOutputSource)
  Value in failed request:  0x47
  Serial number of failed request:  16
  Current serial number in output stream:  17

abbradar · 2016-08-27T19:12:51Z

Try it now. If it doesn't work, I'd be interested in this debug information:

$ systemctl status displaylink
(copy path to the binary)
$ systemctl stop displaylink
$ strace path/to/the/binary

abbradar · 2016-08-27T19:15:10Z

Oh, and another possible fix: add modesetting to videoDrivers.

chris-martin · 2016-08-27T20:33:35Z

Changed nixos config to services.xserver.videoDrivers = [ "displaylink" "modesetting" ];

chris@renzo ~> systemctl status displaylink
● displaylink.service - DisplayLink Manager Service
   Loaded: loaded (/nix/store/zfircz0a4yvv9zgrgjz57cpmdrkhzcag-unit-displaylink.service/displaylink.service; bad; vendor preset: enabled)
   Active: activating (auto-restart) (Result: exit-code) since Sat 2016-08-27 16:31:22 EDT; 4s ago
  Process: 2396 ExecStart=/nix/store/i1sipyqyjd9flmsn181iqdpz6xh3wjpy-displaylink-1.1.62/bin/DisplayLinkManager (code=exited, status=127)
 Main PID: 2396 (code=exited, status=127)

Aug 27 16:31:22 renzo systemd[1]: displaylink.service: Unit entered failed state.
Aug 27 16:31:22 renzo systemd[1]: displaylink.service: Failed with result 'exit-code'.

And from journald:

Aug 27 16:32:36 renzo DisplayLinkManager[2979]: /nix/store/i1sipyqyjd9flmsn181iqdpz6xh3wjpy-displaylink-1.1.62/bin/DisplayLinkManager: error while loading shared libraries: libusb-1.0.so.0: cannot open shared object file: No such file or directory

abbradar · 2016-08-27T20:40:03Z

Fixed.

chris-martin · 2016-08-27T20:58:11Z

Service is up now

chris@renzo ~> systemctl status displaylink
● displaylink.service - DisplayLink Manager Service
   Loaded: loaded (/nix/store/09s6bxhim8d8hnwa7sd6xnfkcjmkqb70-unit-displaylink.service/displaylink.service; bad; vendor preset: enabled)
   Active: active (running) since Sat 2016-08-27 16:44:32 EDT; 2min 15s ago
 Main PID: 952 (.DisplayLinkMan)
   CGroup: /system.slice/displaylink.service
           └─952 /nix/store/4b8pl58v6619ns5il393ibiq7pf1gyls-displaylink-1.1.62/bin/DisplayLinkManager

Aug 27 16:44:32 renzo systemd[1]: Started DisplayLink Manager Service.

There's a lot of output from strace; anything in particular to grep for? Here's some:

strace /nix/store/4b8pl58v6619ns5il393ibiq7pf1gyls-displaylink-1.1.62/bin/DisplayLinkManager 2>&1 | head -n 1000

gist

abbradar · 2016-08-27T21:03:55Z

Let's do it like this:

Start the service with strace from root, grep for "-1" (error) into a file;
With service up like this, plug in the device;
Observe that nothing has changed in XRandr;
Stop the service and upload the log somewhere.

Proprietary software can be difficult to debug D: BTW, have you tried adding modesetting?

chris-martin · 2016-08-27T21:18:28Z

I've add modesetting added since I mentioned it here.

Nothing plugged in, no service running.

chris@renzo ~> xrandr --listproviders
Providers: number : 2
Provider 0: id: 0x47 cap: 0x2, Sink Output crtcs: 3 outputs: 5 associated providers: 0 name:modesetting
Provider 1: id: 0x2ae cap: 0x2, Sink Output crtcs: 1 outputs: 1 associated providers: 0 name:modesetting

strace /nix/store/4b8pl58v6619ns5il393ibiq7pf1gyls-displaylink-1.1.62/bin/DisplayLinkManager 2>&1 | grep "\-1" > /tmp/strace

Plugged in device.

chris@renzo ~> xrandr --listproviders
Providers: number : 2
Provider 0: id: 0x47 cap: 0x2, Sink Output crtcs: 3 outputs: 5 associated providers: 0 name:modesetting
Provider 1: id: 0x2ae cap: 0x2, Sink Output crtcs: 1 outputs: 1 associated providers: 0 name:modesetting

Stopped service.

Strace output

abbradar · 2016-08-31T13:25:03Z

Hm, it looks trimmed (last string is stat("/dev/d). Nevertheless, I don't understand what happens -- first of all, try to create /var/log/displaylink (it tries to access this directory) and look for other log files (I think it left something in /tmp)...

chris-martin · 2016-08-31T13:38:18Z

It writes to /tmp/DisplayLinkManager.log what appears to be a series of base64-encoded lines, but if that's what it is I can't make any sense out of what it decodes to.

The access("/var/log/displaylink/", W_OK) = -1 EACCES (Permission denied) line shows up in the output whether I've previously created a /var/log/displaylink directory or not.

abbradar · 2016-08-31T13:54:16Z

I fear that they encrypt their logfiles.... Yuck!

OK, please do the same but this time upload full strace file somewhere. I'm not sure what else to try short of grepping it for random things...

chris-martin · 2016-08-31T14:24:59Z

There's a support tool, though that itself will require some strace debugging to get it running.

The docs for the support tool do mention that some logs are encrypted.

I don't have an HDMI cable on me, will gather strace output when I get home later.

chris-martin · 2016-09-01T01:55:21Z

I just realized in my last attempt I wasn't running DisplayLinkManager as root, so that accounts for some of the failure -_-

It does seem to require the /var/log/displaylink directory to pre-exist. If I create the directory first and then run DisplayLinkManager, I end up with this:

chris@renzo /v/l/displaylink> ll
total 84K
-rw-r--r-- 1 root root 3.5K Aug 31 21:37 DisplayLinkManager.log
-rw-r--r-- 1 root root  76K Aug 31 21:37 FirmwareTrace.log
-rw-r--r-- 1 root root  256 Aug 31 21:37 'LG TV_GSM0001-2013.1.01010101.edid'

Both log files are encrypted, but the good news is it seems to have at least detected the display (I do indeed have an LG television connected). Output from xrandr commands is unchanged, however.

Full strace: gist. All of that output is from before the displaylink adapter is connected. There is no further strace output produced when it is connected or disconnected.

abbradar · 2016-09-01T10:19:13Z

Hm, I found this thread: http://displaylink.org/forum/showthread.php?t=64550

strace log shows that you do have [libevdi] ioctl: drop_master error=-1 in the output. Maybe that's the problem?

abbradar · 2016-09-01T10:27:49Z

Also, check that your USB device vendor id is 17e9, and check dmesg (maybe something interesting is there).

NixOS/nixpkgs#18041

chris-martin · 2016-09-12T20:29:10Z

I checked the connection of the dock and moved the USB cable in and out at the dock.
Suddently the screens are back!

I've tried two HDMI cables and displays and both USB ports. At this point I'd be surprised if I had a cabling issue.

strace log shows that you do have [libevdi] ioctl: drop_master error=-1 in the output. Maybe that's the problem?

I don't know, it doesn't mean anything to me.

check that your USB device vendor id is 17e9

> lsusb
Bus 002 Device 005: ID 17e9:436f DisplayLink

Looks right.

Kernel log when I plug the thing in:

Sep 12 16:26:20 renzo kernel: usb 2-2: new SuperSpeed USB device number 10 using xhci_hcd
Sep 12 16:26:20 renzo kernel: usb 2-2: New USB device found, idVendor=2109, idProduct=0210
Sep 12 16:26:20 renzo kernel: usb 2-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
Sep 12 16:26:20 renzo kernel: usb 2-2: Product: USB3.0 Hub             
Sep 12 16:26:20 renzo kernel: usb 2-2: Manufacturer: VIA Labs, Inc.         
Sep 12 16:26:20 renzo kernel: hub 2-2:1.0: USB hub found
Sep 12 16:26:20 renzo kernel: hub 2-2:1.0: 1 port detected
Sep 12 16:26:20 renzo kernel: usb 1-2: new high-speed USB device number 11 using xhci_hcd
Sep 12 16:26:20 renzo kernel: usb 1-2: New USB device found, idVendor=2109, idProduct=2210
Sep 12 16:26:20 renzo kernel: usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
Sep 12 16:26:20 renzo kernel: usb 1-2: Product: USB2.0 Hub             
Sep 12 16:26:20 renzo kernel: usb 1-2: Manufacturer: VIA Labs, Inc.         
Sep 12 16:26:20 renzo kernel: hub 1-2:1.0: USB hub found
Sep 12 16:26:20 renzo kernel: hub 1-2:1.0: 4 ports detected
Sep 12 16:26:22 renzo kernel: usb 2-2.1: new SuperSpeed USB device number 11 using xhci_hcd
Sep 12 16:26:22 renzo kernel: usb 2-2.1: New USB device found, idVendor=17e9, idProduct=436f
Sep 12 16:26:22 renzo kernel: usb 2-2.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Sep 12 16:26:22 renzo kernel: usb 2-2.1: Product: Dell 4-in-1 Adapter
Sep 12 16:26:22 renzo kernel: usb 2-2.1: Manufacturer: DisplayLink
Sep 12 16:26:22 renzo kernel: usb 2-2.1: SerialNumber: 1507240231
Sep 12 16:26:22 renzo kernel: usb 2-2.1: Warning! Unlikely big volume range (=511), cval->res is probably wrong.
Sep 12 16:26:22 renzo kernel: usb 2-2.1: [14] FU [Dell USB Audio Playback Volume] ch = 6, val = -8176/0/16
Sep 12 16:26:22 renzo kernel: cdc_ncm 2-2.1:1.5: MAC-Address: 9c:eb:e8:24:a9:f6
Sep 12 16:26:22 renzo kernel: cdc_ncm 2-2.1:1.5: setting rx_max = 16384
Sep 12 16:26:22 renzo kernel: cdc_ncm 2-2.1:1.5: setting tx_max = 16384
Sep 12 16:26:22 renzo kernel: cdc_ncm 2-2.1:1.5 usb0: register 'cdc_ncm' at usb-0000:00:14.0-2.1, CDC NCM, 9c:eb:e8:24:a9:f6
Sep 12 16:26:22 renzo kernel: cdc_ncm 2-2.1:1.5 enp0s20f0u2u1i5: renamed from usb0
Sep 12 16:26:22 renzo kernel: IPv6: ADDRCONF(NETDEV_UP): enp0s20f0u2u1i5: link is not ready
Sep 12 16:26:22 renzo kernel: IPv6: ADDRCONF(NETDEV_UP): enp0s20f0u2u1i5: link is not ready
Sep 12 16:26:22 renzo kernel: evdi: [D] evdi_painter_connect:433 (dev=-1) Connected with           (null)
Sep 12 16:26:22 renzo kernel: evdi: [D] evdi_detect:69 (dev=1) Painter is connected
Sep 12 16:26:22 renzo kernel: evdi: [D] evdi_detect:69 (dev=1) Painter is connected
Sep 12 16:26:22 renzo kernel: evdi: [D] evdi_painter_get_edid_copy:186 (dev=1) 00 ff ff
Sep 12 16:26:25 renzo kernel: cdc_ncm 2-2.1:1.5 enp0s20f0u2u1i5: network connection: disconnected

chris-martin · 2016-09-12T20:35:06Z

Oh! I just ran xrandr --setprovideroutputsource 1 0 and now it's working! 😄

Unfortunately I don't know exactly what the difference is between now and the last time I tried this. Possibilities are:

I'm currently using a different display and a different HDMI cable
This time I built the PR directly, whereas previously I was cherry-picking onto NixOS 16.03

abbradar · 2016-09-12T20:40:44Z

Awesome!

It would be nice to have a cleanup now. First I'll add mkdir -p /var/log/displaylink to the service. Second, try:

Removing modesetting from videoDrivers;
Reverting "Try to fix things" commit;

and see if it works without one or both of them.

chris-martin · 2016-09-12T21:06:47Z

I'm not sure what happened, but I can't build this anymore.

output: https://gist.github.com/chris-martin/6a269a9f6e510cd711f852b671d1295f

abbradar · 2016-09-12T21:29:30Z

Okay, I've found an open-source code drop from DisplayLink here: https://github.com/DisplayLink/evdi. This brings us closer to have no binary blobs and also fixes build on newer kernels. Give it a try now!

abbradar · 2016-09-12T21:30:48Z

Oops, small fix.

chris-martin · 2016-09-12T21:57:48Z

Same result building bc493cc - /tmp/nix-build-displaylink-1.1.62.drv-0/src/evdi/evdi_drv.c:1:0: error: code model kernel does not support PIC mode

abbradar · 2016-09-12T22:00:27Z

Hm, are you sure? This is a path from old version of my package (it should have been module/evdi_drv.c otherwise).

chris-martin · 2016-09-12T22:01:21Z

Oh, whoops, I guess I don't know how to use git pr as well as I thought I did. Just a sec :)

chris-martin · 2016-09-12T22:42:54Z

Looks okay, though one time X crashed when I plugged in the device.

kernel log: https://gist.github.com/chris-martin/7a700a77facc67fbddddee40fbdcc6ba

chris-martin · 2016-09-12T22:44:24Z

I've removed modesetting from videoDrivers and it still works.

abbradar · 2016-09-12T22:44:35Z

Well, I'm not sure what to do with an X crash. Was it one-time event (i.e. can you unplug/plug the device now without crashes)?

chris-martin · 2016-09-12T22:55:01Z

It seems to have been a one-time event.

Unfortunately the performance of this thing seems to be pretty awful. It'll be nice to have for the one-off presentation, but it's pretty much unusable as a full-time display. A really low frame rate, artifacting everywhere on both screens, repositioning the displays sometimes ends in disaster... I'm guessing this is just the device/driver and not much we can do about most of this?

abbradar · 2016-09-12T22:58:53Z

Well, I'm not sure -- I think you can test it with e.g. Ubuntu and see if problems persist. We can investigate it more then.

Either way, let's merge this then now that it more or less works! I'll cherry-pick it to 16.09 too. Thank you for your testing!

chris-martin · 2016-09-12T23:00:33Z

Yeah, good thinking.

Thanks so much for all the work you've put into this!

Close #18041

akaihola · 2021-12-22T07:30:51Z

nixos/modules/hardware/video/displaylink.nix

+
+    powerManagement.powerDownCommands = ''
+      #flush any bytes in pipe
+      while read -n 1 -t 1 SUSPEND_RESULT < /tmp/PmMessagesPort_out; do : ; done;


This line prevents my laptop from going into suspend when there are no DisplayLink devices connected.

See #151706. Unfortunately I can't reproduce this any more. Strange.

NixOS/nixpkgs#18041

abbradar added 0.kind: enhancement 6.topic: nixos 8.has: package (new) 8.has: module (new) labels Aug 27, 2016

abbradar force-pushed the displaylink branch from a7e75e1 to e896a19 Compare August 27, 2016 20:40

chris-martin added a commit to chris-martin/home that referenced this pull request Sep 1, 2016

nix: commented-out displaylink video driver

4008a4d

NixOS/nixpkgs#18041

abbradar force-pushed the displaylink branch from e896a19 to 0a7451a Compare September 12, 2016 21:28

abbradar added 2 commits September 13, 2016 00:30

linuxPackages.displaylink: init at 1.1.62

fbf6a97

displaylink service: init

bc493cc

abbradar force-pushed the displaylink branch from 0a7451a to bc493cc Compare September 12, 2016 21:30

abbradar merged commit bc493cc into NixOS:master Sep 12, 2016

abbradar added a commit that referenced this pull request Sep 12, 2016

Merge branch 'displaylink'

9b26cb9

Close #18041

akaihola reviewed Dec 22, 2021

View reviewed changes

chris-martin added a commit to chris-martin/home that referenced this pull request Mar 25, 2023

nix: commented-out displaylink video driver

4075b98

NixOS/nixpkgs#18041

chris-martin added a commit to chris-martin/home that referenced this pull request Mar 27, 2023

nix: commented-out displaylink video driver

97a4ace

NixOS/nixpkgs#18041

DisplayLink driver and module #18041

DisplayLink driver and module #18041

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abbradar commented Aug 27, 2016

Motivation for this change

Things done

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