[Intel-gfx] [PATCH] drm/i915: Add a bit of locking to intel_dp_hpd_pulse()

[Dave Airlie]

On 31 July 2014 17:37, Daniel Vetter <daniel at ffwll.ch> wrote:
> On Thu, Jul 31, 2014 at 1:49 AM, Dave Airlie <airlied at gmail.com> wrote:
>> Daniel, the only way intel_dp->is_mst can get reset is inside this path.
>
> Ok, so that one should be safe. Then I guess we can just push the
> locking down into the respective non-mst leafs (since atm we do
> link-retraining without any locking, which isn't good). And it needs
> to be dev->mode_config.mutex, not connection mutex.

I'd like to know why we do link training at this point though as well,
adding locking is required of course, I was just going to wrap the
short irq call to the link status check with the lock, but I think it
should be possible to push it down further,

I'm not sure how vague the spec is on what should happen on HPDs, but
if we drop the port clock we obviously will lose the link, but we
should also know not to be retraining it at that point anyways.

Dave.