From mboxrd@z Thu Jan  1 00:00:00 1970
From: Daniel Vetter <daniel@ffwll.ch>
Subject: Re: [PATCH] drm/i915: Seperate fence pin counting from
 normal bind pin counting
Date: Sun, 5 Jun 2011 22:55:29 +0200
Message-ID: <20110605205529.GA2691@phenom.ffwll.local>
References: <1307177743-3195-1-git-send-email-chris@chris-wilson.co.uk>
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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 Sat, Jun 04, 2011 at 09:55:43AM +0100, Chris Wilson wrote:
> +			ret = pin_and_fence_object(obj, ring);
> +			if (ret) {
> +				int ret_ignore;
> +
> +				/* This can potentially raise a harmless
> +				 * -EINVAL if we failed to bind in the above
> +				 * call. It cannot raise -EINTR since we know
> +				 * that the bo is freshly bound and so will
> +				 * not need to be flushed or waited upon.
> +				 */
> +				ret_ignore = i915_gem_object_unbind(obj);
> +				(void)ret_ignore;
> +				WARN_ON(obj->gtt_space);
> +				break;
>  			}

Chris clarified my confusion about this piece of the patch on irc: It's
required to ensure the "valid gtt_space implies that execbuffer_reserve
holds a pin count ref on this object" invariant, which is used later on in
the unwind loop. I think this should be mentioned in the comment. [The
confusion mostly stemmed from the second (slightly different) unwind loop
which is used in an earlier error path.]

I couldn't poke any other holes into this (and I don't have clear ideas
for straightening out the code-flow in execbuffer_reserve) so:

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
-- 
Daniel Vetter
Mail: daniel@ffwll.ch
Mobile: +41 (0)79 365 57 48