[Intel-gfx] [PATCH 3/5] drm/i915: don't return a spurious -EIO from intel_ring_begin

[Chris Wilson]

On Mon, 25 Jun 2012 23:48:01 +0200, Daniel Vetter <daniel at ffwll.ch> wrote:
> So essentially I still fail to see the upside of your proposed ductape
> ... In either case I guess a walk to the reset button is inevitable
> every once in a while ;-)

A false positive for declaring a GPU wedged in a situation that should
have never occurred in the first place is a recoverable and minor
inconvenience compared to locking the display and possibly the system up.

An alternative is to incorporate the deadlock detection into
i915_mutex_lock_interruptible() and make it report -EIO if it waits
longer than 10s, f.e., for the reset to complete. Then the only danger
are the few paths that do not perform the error checking lock.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre