Re: [PATCH] drm/i915: Only clear write-domains after a successful wait-seqno

From: Daniel Vetter <daniel@ffwll.ch>
To: Chris Wilson <chris@chris-wilson.co.uk>
Cc: intel-gfx@lists.freedesktop.org, stable@vger.kernel.org
Subject: Re: [PATCH] drm/i915: Only clear write-domains after a successful wait-seqno
Date: Fri, 28 Jun 2013 18:30:39 +0200	[thread overview]
Message-ID: <20130628163039.GX18285@phenom.ffwll.local> (raw)
In-Reply-To: <1372434848-17653-1-git-send-email-chris@chris-wilson.co.uk>

On Fri, Jun 28, 2013 at 04:54:08PM +0100, Chris Wilson wrote:
> In the introduction of the non-blocking wait, I cut'n'pasted the wait
> completion code from normal locked path. Unfortunately, this neglected
> that the normal path returned early if the wait returned early. The
> result is that read-only waits may return whilst the GPU is still
> writing to the bo.
> 
> Fixes regression from
> commit 3236f57a0162391f84b93f39fc1882c49a8998c7 [v3.7]
> Author: Chris Wilson <chris@chris-wilson.co.uk>
> Date:   Fri Aug 24 09:35:09 2012 +0100
> 
>     drm/i915: Use a non-blocking wait for set-to-domain ioctl
> 
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=66163
> Cc: stable@vger.kernel.org

Queued for -next, thanks for the patch. And do we have an igt for this?
The usual combinaition of some blt busy work with the drmtest interrupt
should be fairly effective I guess ...
-Daniel
> ---
>  drivers/gpu/drm/i915/i915_gem.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 75ab0cb..777c8b9 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -1160,7 +1160,8 @@ i915_gem_object_wait_rendering__nonblocking(struct drm_i915_gem_object *obj,
>  	/* Manually manage the write flush as we may have not yet
>  	 * retired the buffer.
>  	 */
> -	if (obj->last_write_seqno &&
> +	if (ret == 0 &&
> +	    obj->last_write_seqno &&
>  	    i915_seqno_passed(seqno, obj->last_write_seqno)) {
>  		obj->last_write_seqno = 0;
>  		obj->base.write_domain &= ~I915_GEM_GPU_DOMAINS;
> -- 
> 1.8.3.1
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch