Bug 61802 - [uxa] running Xorg -background none with plymouth causes a black screen flickering
Summary: [uxa] running Xorg -background none with plymouth causes a black screen flick...
Status: NEW
Alias: None
Product: xorg
Classification: Unclassified
Component: Driver/intel (show other bugs)
Version: unspecified
Hardware: Other All
: medium normal
Assignee: Chris Wilson
QA Contact: Intel GFX Bugs mailing list
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2013-03-04 16:33 UTC by Frederic Crozat
Modified: 2013-03-05 07:22 UTC (History)
1 user (show)

See Also:
i915 platform:
i915 features:


Attachments
drm.debug=6 dmesg output (75.29 KB, text/plain)
2013-03-04 16:54 UTC, Frederic Crozat
no flags Details

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Description Frederic Crozat 2013-03-04 16:33:12 UTC
This is with intel driver 2.20.19:
00:02.0 VGA compatible controller: Intel Corporation Atom Processor D4xx/D5xx/N4xx/N5xx Integrated Graphics Controller (prog-if 00 [VGA controller])

[    43.928] (--) intel(0): Integrated Graphics Chipset: Intel(R) Pineview GM

When X is being started by gdm, we get a black flickering, despite plymouth correctly retaining splash to prevent this flickering.
Comment 1 Chris Wilson 2013-03-04 16:42:11 UTC
"Correctly" may turn out to be an overstatement. Have you checked drm.debug=6 dmesg to see why the modeset is required?
Comment 2 Frederic Crozat 2013-03-04 16:54:42 UTC
Created attachment 75904 [details]
drm.debug=6 dmesg output

here is the logs.

I've noticed similar flicker on other intel platform, I'll give the debug output later.
Comment 3 Chris Wilson 2013-03-04 17:12:11 UTC
From the kernel perspective, everything worked fine. plymouth triggered a modeset and installed its fb, then X starts and just triggers a set-base rather than a full modeset. That should be seamless (at no point did we power down the pipe to make the changes).

So, the question then becomes did UXA render a visible black frame before filling it with the copy from fbcon?
Comment 4 Frederic Crozat 2013-03-04 17:26:30 UTC
(In reply to comment #3)

> So, the question then becomes did UXA render a visible black frame before
> filling it with the copy from fbcon?

Any way to debug this ?
Comment 5 Chris Wilson 2013-03-04 17:31:23 UTC
Using SNA, --enable-debug=full. Using UXA, switch to SNA... :|
Comment 6 Frederic Crozat 2013-03-04 17:39:22 UTC
(In reply to comment #5)
> Using SNA, --enable-debug=full. Using UXA, switch to SNA... :|

switching to SNA fixed the back flickering..

I'll test on the other hardware where I saw the bug before closing this bug.
Comment 7 Frederic Crozat 2013-03-05 07:22:18 UTC
ok, tested on another system :
00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09) (prog-if 00 [VGA controller])

Switching to SNA fixed the black flicker too..


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