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

ykzhao yakui.zhao at intel.com
Fri Oct 9 09:40:22 CEST 2009

On Tue, 2009-10-06 at 02:21 +0800, Jesse Barnes wrote:
> 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?
The Monitor Detection mode is used in course of TV detection.
After the TV detection is finished, the normal mode is restored. In such
case the TV hotplug stat will be set.
And when the hotplug interrupt is re-enabled, maybe the interrupt will
be triggered again and then the hotplug event is triggered again.

Maybe we should disable the TV hotplug in course of TV detection. Of
course we can disable the hotplug detection for TV.


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