Bug#696176: xserver-xorg-video-radeon: unaccelerated drawing very slow on Radeon HD 7660 with hardware acceleration enabled

[Michel Dänzer]

On Mon, 2012-12-17 at 17:01 +0100, Sascha Silbe wrote: 
> 
> after upgrading the hardware of my desktop, notion (the window
> manager) is abysmally slow. It takes about 2 seconds just to switch
> between two empty desktops. Disabling hardware acceleration altogether
> (Option "NoAccel" "on") makes it reasonably snappy (just a flicker). I
> couldn't find any radeon driver setting (other than NoAccel) that
> would improve the performance (see the commented out lines in
> xorg.conf for what I tried). This is in addition to switching
> ColorTiling off (see #648222 [1]); with ColorTiling enabled,
> performance is even worse.

[...]

> [163321.388] (II) RADEON(0): GPU accel disabled or not working, using shadowfb for KMS

In the log file included in the bug report, acceleration isn't really
enabled according to the above and related lines. Is this the case from
the first time the X server starts after bootup, or only after a while
(maybe related to the below)?


> DRM Information from dmesg:
> ---------------------------
> [77304.456255] [drm] PCIE GART of 512M enabled (table at 0x0000000000040000).
> [77304.474984] [drm] ring test on 0 succeeded in 3 usecs
> [77304.475541] [drm] ib test on ring 0 succeeded in 0 usecs
> [92065.412338] [drm] PCIE GART of 512M enabled (table at 0x0000000000040000).
> [92065.431039] [drm] ring test on 0 succeeded in 3 usecs
> [92065.431568] [drm] ib test on ring 0 succeeded in 0 usecs
> [...]

This looks like the GPU keeps locking up. The basic symptoms of a GPU
lockup and reset are: the display freezes for about 10 seconds, then the
display blanks momentarily while the GPU is reset, then the display
resumes. Have you noticed this, either when doing something in
particular, or randomly?

Does upgrading to libdrm-radeon1 2.4.40-1 from experimental help for
this?


-- 
Earthling Michel Dänzer           |                   http://www.amd.com
Libre software enthusiast         |          Debian, X and DRI developer