Bug#668854: nvidia-glx: Upgrade from 295.33 to 295.40 causes serious performance regression

[Andreas Beckmann]

On 2012-04-15 03:15, Witold Baryluk wrote:
> Updated and now, glxgears gives me something around 5 or 6 fps (previously
> 60+),
> wine games which had easly 50 fps, now had 2, and have serious drawing delay,
> even in 2D mode.

OK, lets see if the problem is caused by teh security fix by applying 
it to 295.33:

Downgrade to 295.33-1 from testing and verify that it still works as
you would expect.

# remove previously built module
dkms remove nvidia/295.33 --all

# download the patch and apply it to the sources
wget ftp://download.nvidia.com/XFree86/patches/security/CVE-2012-0946/nvidia-blacklist-register-mapping-290-295.diff -O - | patch -p1 -d /usr/src/nvidia-295.33/

# rebuild module
dpkg-reconfigure nvidia-kernel-dkms

Thereafter reboot (or ensure otherwise that the new module gets loaded)
and check performance.

To go back to the original (unpatched) 295.33 driver you can run
apt-get install --reinstall nvidia-kernel-dkms=295.33-1
and reboot afterwards.

After this test, please report your issue to NVIDIA, following their 
bug reporting instructions:
http://www.nvnews.net/vbulletin/showthread.php?t=46678
(This should be done while running 295.40)
Include the result of the above test: "295.33 with the security fix
applied does/doesn't show this behavior"
And of course report your findings and a link to a corresponding thread
in the Nvidia forum to this Debian bug report.

Andreas