Need some kernel help...

[Scott Bambrough]

On Thu, 2011-07-07 at 08:39 -0500, Seth Forshee wrote:
> On Wed, Jul 06, 2011 at 01:54:16PM -0600, Tim Gardner wrote:
> > On 07/06/2011 01:45 PM, Scott Bambrough wrote:
> > >Hi guys,
> > >
> > >I did an upgrade from Maverick to Natty on the weekend and ran into a
> > >glitch with HDMI video display.  I filed the following bug if you are
> > >interested:
> > >
> > >https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/805416
> > >
> > >I think it is a kernel issue, related to bad EDID data being returned to
> > >the DRM subsystem.  In particular I think the problem is caused by HDMI
> > >audio being enabled.
> 
> Can you explain what is leading you to conclude that this is due to a
> bad EDID and/or HDMI audio? I'm not all that knowledgable in this area,
> but at a glance I don't see anything on the bug that indicates an
> invalid EDID -- the kernel isn't screaming about bad checksums, and the
> monitor data in Xorg.log looks sane.

This post leads me to believe the problem is HDMI audio is enabled.
http://lists.freedesktop.org/archives/intel-gfx/2010-October/008321.html

See the picture in the bug.

> > >I was looking through the Intel i915 driver to see if I can disable
> > >audio easily.  It looks like there is a way to disable it via a
> > >kernel/module command line option, but I can't seem to figure out how or
> > >what to set.  Is there anyone in your group who might be able to point
> > >me in the right direction?
> 
> Are you referring to the force_audio property? That's the only thing I'm
> seeing that looks related. But it looks like the purpose of that is to
> force HDMI audio to be enabled regardless of what's in the EDID.

Yes that was the property I was looking at.

Scott

-- 
Scott Bambrough <scott.bambrough at linaro.org>
Technical Director, Linaro Landing Teams