Subject: bug#35408: External monitor not working with GDM

From: Ben Sturmfels <[email-masked]>
Date: Wed, 8 May 2019 12:50:11 +1000

On 03/05/19 01:20, Ludovic Courtès wrote:
> Ben Sturmfels <[email-masked]> skribis:
> 
>>> On Fri, 26 Apr 2019, Ludovic Courtès wrote:
>>>> Ben Sturmfels <[email-masked]> skribis:
>>
>>>>> [   448.627] (II) RADEON: Driver for ATI/AMD Radeon chipsets:
>>
>>>> It looks like you have an AMD Radeon graphics card, is that right?  Did
>>>> you pass “modprobe.blacklist=radeon” on the kernel command line, or
>>>> something similar?
>>>>
>>>> Apparently some of these AMD graphics cards are not quite supported by
>>>> free software, so that might be the issue here.
>>>
>>> Whoops, sorry I'm being unintentionally misleading - I shuttle my hard
>>> drive across from my X200 into an F2A85-M motherboard at work, which has
>>> Radeon HD 8470D. It's always just worked with Slim on Guix and Trisquel
>>> 7/8.
>>>
>>> I'll try the modprobe.blacklist though.
>>
>> I tried the modprobe.blacklist=radeon in the kernel line, but GDM still
>> did it's looping thing.
> 
> What .desktop files to you have under /run/current-system/profile?
> 
> There was a bug whereby GDM would enter an infinite loop when no
> .desktop files were provided: <https://issues.guix.info/issue/35068>.

The outcome if this is that I now have GDM working on my X200 + external
monitor, but not on the F2A85-M motherboard + external. For now I'm just
using Slim on the radeon-based system, so I suppose this can be closed.

I think this was two separate issues:

1. I think GDM stopped working on the X200 due to renumbered uid/gids
that caused permission problems on /var/lib/gdm. Not 100% sure - was a
day or two between when I removed /var/lib/gdm and reconfired and when I
tried the external monitor on X200 again.

2. Starting GDM on the F2A85-M gives the following in
/var/log/debug:

May  2 12:19:12 localhost vmunix: [   24.301185] [drm] radeon: 768M of
VRAM memory ready
May  2 12:19:12 localhost vmunix: [   24.301237] [drm] radeon: 1024M of
GTT memory ready.
May  2 12:19:12 localhost vmunix: [   24.301287] [drm] Loading ARUBA
Microcode
May  2 12:19:12 localhost vmunix: [   24.301325] 0000:00:01.0: Missing
Free firmware (non-Free firmware loading is disabled)
May  2 12:19:12 localhost vmunix: [   24.304342] ni_cp: Failed to load
firmware "/*(DEBLOBBED)*/"
May  2 12:19:12 localhost vmunix: [   24.304420] [drm:cayman_init
[radeon]] *ERROR* Failed to load firmware!
May  2 12:19:12 localhost vmunix: [   24.304467] radeon 0000:00:01.0:
Fatal error during GPU init
May  2 12:19:12 localhost vmunix: [   24.304499] [drm] radeon: finishing
device.

And the following in Xorg.0.log:

[   642.963] (II) Module fbdevhw: vendor="X.Org Foundation"
[   642.963] 	compiled for 1.20.4, module version = 0.0.2
[   642.963] 	ABI class: X.Org Video Driver, version 24.0
[   642.963] (EE) open /dev/fb0: No such file or directory
[   642.963] (EE) Screen 0 deleted because of no matching config section.
[   642.963] (II) UnloadModule: "radeon"
[   642.963] (EE) Screen 0 deleted because of no matching config section.
[   642.963] (II) UnloadModule: "modesetting"
[   642.963] (EE) Screen 0 deleted because of no matching config section.
[   642.963] (II) UnloadModule: "fbdev"
[   642.963] (II) UnloadSubModule: "fbdevhw"

Regarding the .desktop issue - I wasn't quite clear on where these files
are supposed to be. I don't seem to have a /run/current-system/profile.
I suppose it doesn't matter now since I've since done a `pull` and
`system reconfigure`.

Thanks!
Ben