Bug 101994

Summary: Weston doesn't start on DisplayLink devices, warns about geometry bounds, and exits for some reason
Product: Wayland Reporter: n3rdopolis <bluescreen_avenger>
Component: westonAssignee: Wayland bug list <wayland-bugs>
Status: RESOLVED NOTOURBUG QA Contact:
Severity: normal    
Priority: medium    
Version: unspecified   
Hardware: Other   
OS: All   
Whiteboard:
i915 platform: i915 features:
Attachments: log of weston trying to start on a udl/displaylink device

Description n3rdopolis 2017-07-31 21:23:48 UTC
Created attachment 133164 [details]
log of weston trying to start on a udl/displaylink device

Hi

I am trying to see if I can start weston on a udl/displaylink 2.0 device
I blacklisted the udlfb driver, in favor of udl, as it has Kernel Mode Setting, and I am trying to test multiseat abilities in Weston.

While it seems the device is working, starting Weston, the screen never lights up. (this might be an issue with the driver??, although the edid is in sysfs. If there is a way to light up the display, and run Weston again...)


It seems that in the log, it states 'bo is out of bounds', and then it exits for some reason, (could be because the screen is off?, Weston does run for a little bit, after the warning...)

I attempted to attach the built in video device to seat1 for now, and start weston with
weston --seat=seat0
for now

I have the full log attached

Thanks
Comment 1 Daniel Stone 2017-08-01 08:26:50 UTC
That log has Weston trying to start on the vmware KMS driver using the DRM backend, so I guess the DisplayLink bit is irrelevant?

Either way, that error message means that the mode being used is 'too big' for VMWare. Looking at the kernel driver, the limits of width/height appear to come from ... somewhere in the VMWare host configuration.
Comment 2 n3rdopolis 2017-08-01 22:24:32 UTC
Odd, Just realizing that. I am not running on a VmWARE device. It's raw hardware. I just forced the udl device to be the only card on the seat. I am just using physical hardware, maybe that's what mesa tried to use as it cannot find udl_drm.so, just noticed that in the log, maybe I need to add that to my mesa... ...if that is in mesa
Comment 3 n3rdopolis 2017-08-01 22:37:04 UTC
I got it to light up the screen (by forcing the pixman renderer), but the screen is blank. In the log it fails to queue page flips (permission denied). I tried to export vblank_mode=1, and that eliminated the errors, however, it's still blank (and running) when I also exported LIB_GL_ALWAYS_SOFTWARE. 

It warns that the computed repaint delay is insane at -338838ms, ...I wonder if this is a driver issue
Comment 4 Daniel Stone 2017-08-02 08:47:58 UTC
Oh heh, I misread slightly. Oh well. Constantly failing pageflips can also be a driver problem. Which raw hardware are you using?
Comment 5 n3rdopolis 2017-08-02 11:00:29 UTC
I am using a Dell laptop. It has an Intel card that it usually works with, but I am trying to run Weston on DisplayLink (it uses the udl) as I want to test things with multiseat.

(For now I just pushed the Intel card into seat1, and ran Weston with Weston --use-pixman --seat=seat0 so it uses the DisplayLink device)

Isn't there an environment variable or something that could be set to attempt to work around the pageflip errors, or was that vblank_mode=1, and I am mistaken
Comment 6 Daniel Stone 2018-06-04 07:03:29 UTC
Sorry, coming back to this - I'm afraid there's nothing you can set in the environment/config to avoid this. We have a hard reliance on pageflips working with delayed completion events.

udl doesn't currently implement this from what I understand, but there are multiple people working on replacing that driver with something which would actually work for us.
Comment 7 n3rdopolis 2018-07-24 23:24:25 UTC
Out of curiosity, would that be something like SimpleDRM?

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