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authorEric Anholt <eric@anholt.net>2011-11-07 16:07:04 -0800
committerGreg Kroah-Hartman <gregkh@suse.de>2011-12-09 08:52:21 -0800
commitd37e37738433032fd7206b238c49c73969afc283 (patch)
treea95b4973ea17b872053ddaf69f7d4048741a51a6
parenta00931691a6f42ddfd8e677ba30b4dbfa705b47b (diff)
downloadlwn-d37e37738433032fd7206b238c49c73969afc283.tar.gz
lwn-d37e37738433032fd7206b238c49c73969afc283.zip
drm/i915: Turn on a required 3D clock gating bit on Sandybridge.
commit 406478dc911e16677fbd9c84d1d50cdffbc031ab upstream. Fixes rendering failures in Unigine Tropics and Sanctuary and the mesa "fire" demo. Signed-off-by: Eric Anholt <eric@anholt.net> Signed-off-by: Keith Packard <keithp@keithp.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--drivers/gpu/drm/i915/i915_reg.h3
-rw-r--r--drivers/gpu/drm/i915/intel_display.c9
2 files changed, 12 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 8936d40d2257..fb87b3c9d38b 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -3370,6 +3370,9 @@
#define GT_FIFO_FREE_ENTRIES 0x120008
+#define GEN6_UCGCTL2 0x9404
+# define GEN6_RCPBUNIT_CLOCK_GATE_DISABLE (1 << 12)
+
#define GEN6_RPNSWREQ 0xA008
#define GEN6_TURBO_DISABLE (1<<31)
#define GEN6_FREQUENCY(x) ((x)<<25)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 853bddb96ea9..6e1165a436ec 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -7405,6 +7405,15 @@ static void gen6_init_clock_gating(struct drm_device *dev)
I915_WRITE(WM2_LP_ILK, 0);
I915_WRITE(WM1_LP_ILK, 0);
+ /* According to the BSpec vol1g, bit 12 (RCPBUNIT) clock
+ * gating disable must be set. Failure to set it results in
+ * flickering pixels due to Z write ordering failures after
+ * some amount of runtime in the Mesa "fire" demo, and Unigine
+ * Sanctuary and Tropics, and apparently anything else with
+ * alpha test or pixel discard.
+ */
+ I915_WRITE(GEN6_UCGCTL2, GEN6_RCPBUNIT_CLOCK_GATE_DISABLE);
+
/*
* According to the spec the following bits should be
* set in order to enable memory self-refresh and fbc: