[PATCH] drm: Add locking to resume_force_mode to prevent multiple

[Chris Wilson]

On Thu, 22 Mar 2012 18:25:55 -0400, Sean Paul <seanpaul at chromium.org> wrote:
> Add a mutex to protect resume_force_mode from being called multiple
> times. This fixes a bug observed on SNB where two wake sources call
> resume_force_mode and the FDI training fails as a result. The user
> facing result of this is complete screen corruption.

Looks like a bug in i915_drv.c for calling that function without holding
the mode_config.lock
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre