regression: 2.6.35-rc1 hangs on i865G with KMS

[Ondrej Zary]

On Saturday 05 June 2010 02:23:27 Eric Anholt wrote:
> On Fri, 4 Jun 2010 22:01:28 +0200, Ondrej Zary <linux at rainbow-software.org> 
wrote:
> > Hello,
> > I'm testing 2.6.35-rc1 kernel on Asus P4P800-VM (i865G chipset). After
> > loading i915 module, the screen goes blank and the kernel hangs
> > completely (same with 2.6.35-rc1-git2). This does not happen with
> > "i915.modeset=0" parameter.
> >
> > This problem does not appear with 2.6.34. Is this a known regression?
>
> Not known as far as I know -- we'd enjoy a bisect with a bug report on
> bugs.freedesktop.org.

I don't like that place - from 13 bugs I have reported there, 11 are still 
open :( I even provided a patch for one and nobody cares...

Bisect reveals two possible bad commits:
386516744ba45d50f42c6999151cc210cb4f96e4
drm/fb: fix fbdev object model + cleanup properly

or
8be48d924c307e72e3797ab5bde81b07a1ccc52d
drm/kms/fb: move to using fb helper crtc grouping instead of core crtc list

It depends on the last step of bisection - that kernel hangs but in a 
different way - the monitor has no signal (in every other case, the monitor 
was just blank).

Reverting these commits is not possible.

-- 
Ondrej Zary