Bug 47067

Summary: Black flickering on LVDS of Acer Aspire 7560G with R600g
Product: xorg Reporter: russianneuromancer
Component: Driver/RadeonAssignee: xf86-video-ati maintainers <xorg-driver-ati>
Status: RESOLVED WORKSFORME QA Contact: Xorg Project Team <xorg-team>
Severity: normal    
Priority: medium CC: hramrach
Version: 7.6 (2010.12)   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:

Description russianneuromancer 2012-03-07 10:16:22 UTC 
Hardware:
Acer Aspire 7560G, A8-3500M - Radeon HD 6620G, external display attached via HDMI.

Software:
That laptop is supported since Linux 3.2, so because of that I use it for four months with Kubuntu 11.10, Linux 3.2, Xorg Edgers PPA, KDE 4.7. Now I upgrade to Kubuntu 12.04 with Linux 3.2, Mesa 8.0.1, KDE 4.8 and issue almost the same (but flickering is less often than before).

Steps to reproduce:
In November and December (with latest at this moment R600g from Xorg Edgers PPA and KDE 4.7)  issue is reproduceable even when I click to Kickoff or minimize/maximize apps (it still happen sometimes but very rare). Now (with default driver in Kubuntu 12.04 and KDE 4.8) steps to reproduce is a little different but that still easy - flickering is reproduceable when KWin playback animation of "carousel", "desktop cube", "slide back" (and probably many others) effects.

How that black flickering looks like:
It's looks like black rectangle/polygon that cover 1/3 of display in the middle or bottom.

Additinal information:
Discrete GPU is disabled on every boot by script. Usually I use DynPM power profile for GPU in APU, but that probably unrelated to this issue, because with default profile issue looks the same.
Issue is reproduceable only with OpenGL version of KWin. There is no black flickering on LVDS with OpenGL ES version of KWin. Issue is also visible only on LVDS, never on external display that attached to HDMI (that selected as main in KDE display settings). Issue is also reproduceable when external display is not attached.
There is no black flickering on LVDS with fglrx.
Comment 1 Alex Deucher 2012-03-07 12:08:58 UTC 
Sounds like it may be related to the display watermarks.  Does booting with radeon.disp_priority=2 on the kernel command line in grub help?
Comment 2 russianneuromancer 2012-03-07 13:28:06 UTC 
> Does booting with radeon.disp_priority=2 on the kernel command line in grub help?
Yes, it help a lot - with radeon.disp_priority=2 I get only one flicker (when I press Alt+Tab first time after login, when system is still under heavy load) and no flickering after that (at least at this moment).
Comment 3 russianneuromancer 2012-11-02 06:15:04 UTC 
With stock Kubuntu 12.10 kernel (3.0.0-17) this issue is not reproducible anymore, even without "radeon.disp_priority=2".

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