KMS/radeon regression: failure to set modes on CEDAR & TAHITI; v3.11 vs 3.12-rc5/rc7

[Robin H. Johnson]

On Wed, Nov 06, 2013 at 05:37:11PM -0500, Jerome Glisse wrote:
> On Wed, Nov 06, 2013 at 05:48:55PM +0000, Robin H. Johnson wrote:
> > On Wed, Nov 06, 2013 at 12:16:31PM -0500, Alex Deucher wrote:
> > > On Wed, Nov 6, 2013 at 12:14 PM, Robin H. Johnson <robbat2 at gentoo.org> wrote:
> > > > (Resending to dri-devel because the first one didn't make it).
> > > >
> > > > I apologize for not sending this sooner, but I wanted to be really sure that I
> > > > wasn't introducing the bug elsewhere, and I was lacking time to even narrow it
> > > > down this far.
> > > >
> > > > TL;DR:
> > > > 3.11 kernel does proper modeset for dual 1920x1200 outputs
> > > > 3.12-rc5/rc7 kernel fails to do proper modeset, blank screen after radeon loaded
> > > Can you bisect?
> > I have the next step in the bisect prepared (taking an educated guess
> > and deciding that rc1 was probably also bad, because the changes after
> > rc1 were minimal), but this is my primary box for getting work done; so
> > I haven't rebooted since writing my email and preparing that next
> > kernel.
> Culprit likely d1e3b5564834ea24dee6b364a172365f64865fe5 try reverting that one.
Confirmed as the buggy commit via bisect.
Then reverted in 3.12 and 3.12 suddenly works.

-- 
Robin Hugh Johnson
Gentoo Linux: Developer, Trustee & Infrastructure Lead
E-Mail     : robbat2 at gentoo.org
GnuPG FP   : 11ACBA4F 4778E3F6 E4EDF38E B27B944E 34884E85