Bug 75649

Problem persists even when using 3.14 kernel and mesa 10.1 in Arch.

What other information would be useful to assist in debugging this issue?

Please attach your xorg log and dmesg output.

Does it work any better with a 3.15 kernel from this tree:
http://cgit.freedesktop.org/~deathsimple/linux/log/?h=drm-fixes-3.15-wip

Created attachment 97429 [details]
Xorg log

Created attachment 97430 [details]
dmesg output

Here are the logs. I'll try out the new kernel soon.

I get the same problems as described before with two different monitors. Using an up-to-date Arch Linux with kernel 3.14 (also tried kernel 3.15rc2) with a hd3470 card. Problem occurs only, if an external monitor is connected at resolution 1920x1080@60Hz in single mode (extended mode makes no problems). Funny enough when using 1920x1080@50Hz in single mode everything seems also fine. By switching back to Catalyst the problem doesn't occur.

Found some similar threads:
https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1209315
https://bugs.freedesktop.org/show_bug.cgi?id=42621

By disabling color tiling and dpm the phenomenon appears only when switching between modes (monitors on / off). So in this case when starting the laptop with closed lid everything is ok, until switching between modes.

I can confirm that only switching modes to 1920x1080 causes the issue. The latest I have tested is Arch 3.15.5, Cinnamon desktop, Mesa 10.2.4, and xf86-video-ati 1:7.4.0. Maybe this is an xrandr issue?

I have been looking in the xf86-video-ati repo at drmmode_display.c and the drmmode_sf86crtc_resize() function but can't find anything so far.

It seems from Paul's comments that the issue may be related to the refresh rate as well. Are there any suggestion as to places to look in the code?

(In reply to comment #8)
> I have been looking in the xf86-video-ati repo at drmmode_display.c and the
> drmmode_sf86crtc_resize() function but can't find anything so far.
> 
> It seems from Paul's comments that the issue may be related to the refresh
> rate as well. Are there any suggestion as to places to look in the code?

Everything that touches the hw is in the kernel driver.  Does disabling dpm fix the issue?

If you are using dpm, make sure your ddx has this patch:
http://cgit.freedesktop.org/xorg/driver/xf86-video-ati/commit/?id=c4ae0e2cbcc0e2ebf9f13ee92d59b5120254a1dc

(In reply to comment #10)
> If you are using dpm, make sure your ddx has this patch:
> http://cgit.freedesktop.org/xorg/driver/xf86-video-ati/commit/
> ?id=c4ae0e2cbcc0e2ebf9f13ee92d59b5120254a1dc

I am using the latest ddx from git. Enabling or disabling dpm using the kernel option radeon.dpm=1 or radeon.dpm=0 does not help. It seems like the more redraws the GPU has to do, the worse things get. For example, sitting at the desktop with nothing moving is fine. Opening chromium, many horizontal lines matching the color of whatever is on the screen begin to flicker on and off.

Is it possible that color tiling is the culprit as described in https://bugs.freedesktop.org/show_bug.cgi?id=42621

His symptoms sound identical (only happens on 1920x1080 resolution, smaller resolutions work).

OK so I disabled color tiling in my xorg.conf and that worked. Disabling color tiling 2D did not work.

So it seems to be an issue with 1D color tiling and single 1920x1080 resolution monitor at 60Hz refresh rate.

I changed refresh rate to 50Hz using xrandr and that fixed the issue as well (pointed out by Paul previously).

Does booting with radeon.disp_priority=2 on the kernel command line in grub help?

(In reply to comment #13)
> Does booting with radeon.disp_priority=2 on the kernel command line in grub
> help?

That fixes it. Thanks.

Do you have any idea why this happens with a single monitor but not a duel setup?

-- GitLab Migration Automatic Message --

This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity.

You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.freedesktop.org/drm/amd/issues/453.