[ 3.8.y.z extended stable ] Patch "drm/i915: Only clear write-domains after a successful wait-seqno" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    drm/i915: Only clear write-domains after a successful wait-seqno

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.5.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From d26b581b6852ac439bbf5bc514c584eaf1be2cdb Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris at chris-wilson.co.uk>
Date: Fri, 28 Jun 2013 16:54:08 +0100
Subject: drm/i915: Only clear write-domains after a successful wait-seqno

commit daa13e1ca587bc773c1aae415ed1af6554117bd4 upstream.

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 at 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 at chris-wilson.co.uk>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=66163
Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 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 3b9d18b..80bc298 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1164,7 +1164,8 @@ 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;
--
1.8.1.2