[ 3.5.yuz extended stable ] Patch "drm/i915: Set guardband clipping workaround bit in the right" has been added to staging queue

Herton Ronaldo Krzesinski herton.krzesinski at canonical.com
Wed Nov 21 05:08:33 UTC 2012

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

    drm/i915: Set guardband clipping workaround bit in the right

to the linux-3.5.y-queue branch of the 3.5.yuz extended stable tree 
which can be found at:


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

For more information about the 3.5.yuz tree, see



>From 0a650a6977d6b2205d532fa74c3e6d8607768970 Mon Sep 17 00:00:00 2001
From: Kenneth Graunke <kenneth at whitecape.org>
Date: Sun, 7 Oct 2012 08:51:07 -0700
Subject: [PATCH] drm/i915: Set guardband clipping workaround bit in the right

commit 26b6e44afb58432a5e998da0343757404f9de9ee upstream.

A previous patch, namely:

commit bf97b276ca04cee9ab65ffd378fa8e6aedd71ff6
Author: Daniel Vetter <daniel.vetter at ffwll.ch>
Date:   Wed Apr 11 20:42:41 2012 +0200

    drm/i915: implement w/a for incorrect guarband clipping

accidentally set bit 5 in 3D_CHICKEN, which has nothing to do with
clipping.  This patch changes it to be set in 3D_CHICKEN3, where it

The game "Dante" demonstrates random clipping issues when guardband
clipping is enabled and bit 5 of 3D_CHICKEN3 isn't set.  So the
workaround is actually necessary.

Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
Cc: Oliver McFadden <oliver.mcfadden at linux.intel.com>
Acked-by: Paul Menzel <paulepanter at users.sourceforge.net>
Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
Reviewed-by: Mika Kuoppala <mika.kuoppala at intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski at canonical.com>
 drivers/gpu/drm/i915/i915_reg.h |    2 +-
 drivers/gpu/drm/i915/intel_pm.c |    4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 4cad908..84c04c8 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -508,7 +508,7 @@
 # define _3D_CHICKEN2_WM_READ_PIPELINED			(1 << 14)
 #define _3D_CHICKEN3	0x02090

 #define MI_MODE		0x0209c
 # define VS_TIMER_DISPATCH				(1 << 6)
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index b55aa0e..f8e332d 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3334,8 +3334,8 @@ static void gen6_init_clock_gating(struct drm_device *dev)

 	/* Bspec says we need to always set all mask bits. */
-	I915_WRITE(_3D_CHICKEN, (0xFFFF << 16) |
+	I915_WRITE(_3D_CHICKEN3, (0xFFFF << 16) |

 	 * According to the spec the following bits should be

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