[Intel-gfx] [PATCH, RFC] Output hotplug support

[Jesse Barnes]

On Mon, 05 Oct 2009 14:05:34 -0400
Adam Jackson <ajax at redhat.com> wrote:

> I'm shipping the following patch in Fedora 12 to enable output
> hotplug:
> 
> http://cvs.fedoraproject.org/viewvc/F-12/xorg-x11-drv-intel/uevent.patch?revision=1.1
> 
> And it pretty much works!  We get hotplug events from the DRM, rescan
> RANDR when that happens, events go out, userspace adapts.  It's all
> quite cool.  It's not really mergeable yet for all the reasons in the
> comments in the patch itself, but it's a start.

There are events for other stuff these days, including hangs and
errors.  Just checking the environment for HOTPLUG=1 should be
sufficient.

> 
> However, in order to actually ship this, I had to also ship this for
> the kernel:
> 
> http://cvs.fedoraproject.org/viewvc/F-12/kernel/drm-intel-no-tv-hotplug.patch?revision=1.1
> 
> Otherwise, I'd get stuck in a loop where (afaict) output scan would
> trigger a TV interrupt, which would trigger a scan, etc.  TV load
> detection not being the fastest thing in the world, X would process
> requests ve-ry slow-ly.
> 
> If anyone actually understands the TV output code and wanted to take a
> look at this, I'd appreciate it.

I know I had it working at one point, but there have been a lot of
changes to the KMS TV code since then.  I'll take a look.  Sounds like
the fundamental bug is that TV scanning causes a TV hotplug event?

-- 
Jesse Barnes, Intel Open Source Technology Center