[PATCH 03/17] drm: convert crtc and mode_config to ww_mutex

[Daniel Vetter]

On Mon, May 26, 2014 at 5:04 PM, Rob Clark <robdclark at gmail.com> wrote:
> hmm, ok, I had thought this case, thread B would get -EDEADLK because
> lock was held, and not his acquire ctx.  If that is not the case, then
> I would propose this:
>
> All places doing things the old way, must grab mode_config.mutex first
> currently.  And we use mode_config.mutex to protect
> mode_config.acquire_ctx.  So all the lower spots grabbing individual
> crtc mutexes can safely use mode_config.acquire_ctx.
>
> Then the only headache is propagating -EDEADLK up the call stack.  If
> we are lucky, the all already propagate -EINTR, etc.

The output poll work most definitely doesn't propagate -EINTR. Like
I've said, this will be painful. And imo doing this also makes the kms
locking into quite a mess overall.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch