From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ben Widawsky <ben@bwidawsk.net>
Subject: Re: [PATCH 1/5] drm/i915: downgrade non-lethal BUG_ONs
Date: Wed, 20 Apr 2011 07:27:24 -0700
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To: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>, intel-gfx@lists.freedesktop.org
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On Wed, Apr 20, 2011 at 09:18:03AM +0100, Chris Wilson wrote:

> > diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> > index 316603e..8cac87c 100644
> > --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> > +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> > @@ -1093,7 +1093,7 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
> >  								&objects, eb,
> >  								exec,
> >  								args->buffer_count);
> > -			BUG_ON(!mutex_is_locked(&dev->struct_mutex));
> > +			WARN_ON(!mutex_is_locked(&dev->struct_mutex));
> 
> I think this can be dropped after close inspection of the call path.
> 

Is that right? There are definitely cases where the mutex is released
and not reacquired. You would know better than I if those cases can
occur in a normal system. Assuming they can, Won't we just BUG_ON when
we try to release struct_mutex?

> -Chris
> 

Ben