Re: Slow Firefox redraw in Debian testing

[debiancbien <debiancbien@gmail.com>]

On Sat, Apr 03, 2010 at 03:57:59PM -0400, Stefan Monnier wrote:
> I've recently noticed that Firefox redraw is *really* slow on
> my Debian testing machines.
> I'm not sure if it's only Firefox or if it also affects some
> other applications.  It doesn't seem specific to a particular X driver
> (I see it both with "nv" and with "radeon").
> 
> I almost get the impression that it could be a problem somewhere in Gtk
> or somesuch thing.

You don't give much details so i'll just point you to a possible
cause/workaround which worked for me :

New kernel comes with kms (kernel mode-setting, since 2.32 or 33, not
sure) and apparently, the xserver-xorg-video-radeon driver (6-12-192) is
not yet compatible with it. So the workaround was to do (any or all of,
can't remember) :

* in /etc/modules, comment the line 'radeon modeset=1'

* in /etc/modprobe.d/radeon-kms, comment the line containing
  'options radeon modeset'...

If i don't use this workaround, i have same "symptoms" as yours, as well
as errors in Xorg.0.log about DRI and errors in dmesg about drm.

Good luck!