Bug 92478 - xorg-server-1.17.2 no longer detects Radeon card: blank screen
Summary: xorg-server-1.17.2 no longer detects Radeon card: blank screen
Status: RESOLVED FIXED
Alias: None
Product: xorg
Classification: Unclassified
Component: Server/DDX/Xorg (show other bugs)
Version: unspecified
Hardware: x86-64 (AMD64) Linux (All)
: medium normal
Assignee: Xorg Project Team
QA Contact: Xorg Project Team
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2015-10-15 19:28 UTC by Attila Tóth
Modified: 2015-11-15 23:26 UTC (History)
1 user (show)

See Also:
i915 platform:
i915 features:


Attachments
working Xorg log file 1.17.1 (56.24 KB, text/plain)
2015-10-16 11:59 UTC, Attila Tóth
no flags Details
failing Xorg log file 1.17.2 (20.45 KB, text/plain)
2015-10-16 12:00 UTC, Attila Tóth
no flags Details
corresponding xorg.conf (33.79 KB, text/plain)
2015-10-16 12:01 UTC, Attila Tóth
no flags Details

Description Attila Tóth 2015-10-15 19:28:36 UTC
I experience the symptom on two systems (FirePro V4800 and FirePro M5950).
xorg-server-1.17.1 runs fine:
Upgrading to 1.17.2 results in blank screen.
relevant log snippet:
(II) modeset(G0): using drv /dev/dri/card0
(EE) No devices detected.

while 1.17.1 show this:
(WW) Falling back to old probe method for modesetting
(II) [KMS] Kernel modesetting enabled.
...
Comment 1 Attila Tóth 2015-10-15 19:29:49 UTC
I was asked to do a bisect in another bug by Michel Dänzer.

2ce54b81391d36856641c2691bcae8bd13daba4c is the first bad commit
commit 2ce54b81391d36856641c2691bcae8bd13daba4c
Author: Aaron Plattner <aplattner@nvidia.com>
Date:   Tue Dec 30 09:13:16 2014 -0800

    xfree86: Add GPU screens even if there are no active GDevs

    xf86platformProbeDev creates GPU screens for any platform devices that were not
    matched by a GDev in the loop above, but only if there was at least one device.
    This means that it's impossible to configure a device as a GPU screen if there
    is only one platform device that matches that driver.

    Instead, create a GPU screen (if possible) for any platform device that was not
    claimed by the GDev loop.

    Signed-off-by: Aaron Plattner <aplattner@nvidia.com>
    Reviewed-by: Maarten Lankhorst <maarten.lankhorst@ubuntu.com>
    Acked-by: Alex Deucher <alexander.deucher@amd.com>
    (cherry picked from commit e36236eade412dd3894f75f78a7b3d7c1037e6c3)

:040000 040000 f5fbff105eb8dd75a0f8af3ec3f4072e9e2877d5 3d7f6e8225e0559ffe5e2bd69317f9dc521b3450 M      hw
Comment 2 Attila Tóth 2015-10-15 19:31:21 UTC
So the culprit commit looks like to be this:
http://cgit.freedesktop.org/xorg/xserver/commit/?id=e36236eade412dd3894f75f78a7b3d7c1037e6c3

May it be a problem with my particular configuration?

What should I do/test next?

Thanks: Dwokfur
Comment 3 Attila Tóth 2015-10-15 19:32:35 UTC
This is the place from where this new bug report diverged:
https://bugs.freedesktop.org/show_bug.cgi?id=92168#c14
Comment 4 Michel Dänzer 2015-10-16 02:24:39 UTC
Attila, please attach the Xorg.0.log and xorg.conf files corresponding to the problem to this report.

Aaron, any ideas?
Comment 5 Attila Tóth 2015-10-16 11:59:58 UTC
Created attachment 118915 [details]
working Xorg log file 1.17.1
Comment 6 Attila Tóth 2015-10-16 12:00:20 UTC
Created attachment 118916 [details]
failing Xorg log file 1.17.2
Comment 7 Attila Tóth 2015-10-16 12:01:15 UTC
Created attachment 118917 [details]
corresponding xorg.conf
Comment 8 Attila Tóth 2015-10-16 12:04:33 UTC
(In reply to Michel Dänzer from comment #4)
> Attila, please attach the Xorg.0.log and xorg.conf files corresponding to
> the problem to this report.
> 
> Aaron, any ideas?

Please forgive me, that the config file may have some atavistic remnants from the last century, although I try to keep it as up to date as possible.
Comment 9 Michel Dänzer 2015-10-19 03:42:21 UTC
Does Xorg start up if you move the xorg.conf file away such that Xorg doesn't pick it up?
Comment 10 Aaron Plattner 2015-10-21 23:22:47 UTC
Hmm, yeah, that's strange.  I don't know why the server would be picking up modesetting as a GPU screen before picking up radeon as a real screen here.  I would also be curious to see if this reproduces without an xorg.conf file.
Comment 11 Attila Tóth 2015-10-25 01:27:01 UTC
(In reply to Michel Dänzer from comment #9)
> Does Xorg start up if you move the xorg.conf file away such that Xorg
> doesn't pick it up?

Xorg does start up after I move xorg.conf, so it doesn't pick it up. I'm curious to figure out why.
Comment 12 Attila Tóth 2015-10-25 01:30:42 UTC
(In reply to Aaron Plattner from comment #10)
> Hmm, yeah, that's strange.  I don't know why the server would be picking up
> modesetting as a GPU screen before picking up radeon as a real screen here. 
> I would also be curious to see if this reproduces without an xorg.conf file.

It might be caused by the module loading section of my culprit xorg.conf. I try to figure that out.
After moving xorg.conf so that the server doesn't pick it up the first loaded module is ati and then comes radeon. That is a difference compared to the hand-crafted config.

Is there anything I may further test for you before somebody closes this bug?
Comment 13 post 2015-11-14 09:19:08 UTC
This is some blind guess by a guest but you may try:

Section "ServerFlags"
    Option "AutoAddGPU" "off"
EndSection

The AutoAddGPU function seems to add additional non-existing devices to existing ones while changing their interface type/number. But this may be completely wrong, don't rely on that!
Comment 14 Attila Tóth 2015-11-15 23:25:29 UTC
(In reply to post from comment #13)
> This is some blind guess by a guest but you may try:
> 
> Section "ServerFlags"
>     Option "AutoAddGPU" "off"
> EndSection
> 
> The AutoAddGPU function seems to add additional non-existing devices to
> existing ones while changing their interface type/number. But this may be
> completely wrong, don't rely on that!

Thanks for the tip.
Since removing the Xorg config file solved the crashes I compared the logs and noticed the modules were loaded differently. It was disturbing, that although Xorg could figure out the hardware I have, it couldn't figure out how my displays are arranged. After I've modified my xorg.conf to reflect the proper module loading sequence it solved crashing problems and also ensured proper arrangement of my displays at the same time.

BR: Dw.
Comment 15 Attila Tóth 2015-11-15 23:26:07 UTC
The crashes were caused by a configuration file issue.


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