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authorDave Airlie <airlied@redhat.com>2010-07-20 13:15:31 +1000
committerDave Airlie <airlied@redhat.com>2010-07-20 15:24:18 +1000
commit944001201ca0196bcdb088129e5866a9f379d08c (patch)
treeeb8b2b2a9b00f469c283c5714c6d642db8aaa46b /drivers
parent45503ded966c98e604c9667c0b458d40666b9ef3 (diff)
drm/i915: enable low power render writes on GEN3 hardware.
A lot of 945GMs have had stability issues for a long time, this manifested as X hangs, blitter engine hangs, and lots of crashes. one such report is at: https://bugs.freedesktop.org/show_bug.cgi?id=20560 along with numerous distro bugzillas. This only took a week of digging and hair ripping to figure out. Tracked down and tested on a 945GM Lenovo T60, previously running x11perf -copypixwin500 or x11perf -copywinpix500 repeatedly would cause the GPU to wedge within 4 or 5 tries, with random busy bits set. After this patch no hangs were observed. cc: stable@kernel.org Signed-off-by: Dave Airlie <airlied@redhat.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/gpu/drm/i915/i915_gem.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 074385882ccf..43ce3809ef64 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4741,6 +4741,16 @@ i915_gem_load(struct drm_device *dev)
list_add(&dev_priv->mm.shrink_list, &shrink_list);
spin_unlock(&shrink_list_lock);
+ /* On GEN3 we really need to make sure the ARB C3 LP bit is set */
+ if (IS_GEN3(dev)) {
+ u32 tmp = I915_READ(MI_ARB_STATE);
+ if (!(tmp & MI_ARB_C3_LP_WRITE_ENABLE)) {
+ /* arb state is a masked write, so set bit + bit in mask */
+ tmp = MI_ARB_C3_LP_WRITE_ENABLE | (MI_ARB_C3_LP_WRITE_ENABLE << MI_ARB_MASK_SHIFT);
+ I915_WRITE(MI_ARB_STATE, tmp);
+ }
+ }
+
/* Old X drivers will take 0-2 for front, back, depth buffers */
if (!drm_core_check_feature(dev, DRIVER_MODESET))
dev_priv->fence_reg_start = 3;