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authorKenneth Graunke <kenneth@whitecape.org>2012-04-27 12:44:41 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-05-07 08:53:21 -0700
commit6a4ddbfcd27b7190182ef7ce9464af8c93043cb9 (patch)
tree72e372e0e83b58ca8de5c8b4a511bc5f02ae8326 /drivers
parentf3cf624ecd3eac5e787c61ef518232d04c34b61f (diff)
drm/i915: Set the Stencil Cache eviction policy to non-LRA mode.
commit 3a69ddd6f872180b6f61fda87152b37202118fbc upstream. Clearing bit 5 of CACHE_MODE_0 is necessary to prevent GPU hangs in OpenGL programs such as Google MapsGL, Google Earth, and gzdoom when using separate stencil buffers. Without it, the GPU tries to use the LRA eviction policy, which isn't supported. This was supposed to be off by default, but seems to be on for many machines. This cannot be done in gen6_init_clock_gating with most of the other workaround bits; the render ring needs to exist. Otherwise, the register write gets dropped on the floor (one printk will show it changed, but a second printk immediately following shows the value reverts to the old one). Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=47535 Cc: Rob Castle <futuredub@gmail.com> Cc: Eric Appleman <erappleman@gmail.com> Cc: aaron667@gmx.net Cc: Keith Packard <keithp@keithp.com> Signed-off-by: Kenneth Graunke <kenneth@whitecape.org> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Dave Airlie <airlied@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/gpu/drm/i915/i915_reg.h1
-rw-r--r--drivers/gpu/drm/i915/intel_ringbuffer.c8
2 files changed, 9 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 3e6429a4dbe7..ac38d2113521 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -523,6 +523,7 @@
#define CM0_MASK_SHIFT 16
#define CM0_IZ_OPT_DISABLE (1<<6)
#define CM0_ZR_OPT_DISABLE (1<<5)
+#define CM0_STC_EVICT_DISABLE_LRA_SNB (1<<5)
#define CM0_DEPTH_EVICT_DISABLE (1<<4)
#define CM0_COLOR_EVICT_DISABLE (1<<3)
#define CM0_DEPTH_WRITE_DISABLE (1<<1)
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index cbc3c049611e..99f71aff174b 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -417,6 +417,14 @@ static int init_render_ring(struct intel_ring_buffer *ring)
if (INTEL_INFO(dev)->gen >= 6) {
I915_WRITE(INSTPM,
INSTPM_FORCE_ORDERING << 16 | INSTPM_FORCE_ORDERING);
+
+ /* From the Sandybridge PRM, volume 1 part 3, page 24:
+ * "If this bit is set, STCunit will have LRA as replacement
+ * policy. [...] This bit must be reset. LRA replacement
+ * policy is not supported."
+ */
+ I915_WRITE(CACHE_MODE_0,
+ CM0_STC_EVICT_DISABLE_LRA_SNB << CM0_MASK_SHIFT);
}
return ret;