[0296/1094] drm/i915: Add a partial instruction shootdown workaround on Broadwell.

Commit Message

Dheeraj Jamwal Oct. 21, 2014, 10:48 a.m. UTC

From: Kenneth Graunke <[e-mail]>

I believe this will be necessary on production hardware.

Signed-off-by: Kenneth Graunke <[e-mail]>
Reviewed-by: Ville Syrjälä <[e-mail]>
Reviewed-by: Ben Widawsky <[e-mail]>
[danvet: Fix whitespace fail spotted by checkpatch. Also add missing
:bdw w/a tag that Ville spotted.]
Signed-off-by: Daniel Vetter <[e-mail]>
(cherry picked from commit c8966e1058e1e8ae2eec4211157847032829697a)

Signed-off-by: Dheeraj Jamwal <[e-mail]>
---
 drivers/gpu/drm/i915/i915_reg.h |    3 +++
 drivers/gpu/drm/i915/intel_pm.c |    4 ++++
 2 files changed, 7 insertions(+)

Patch

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index e313035..d575baf 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -5048,6 +5048,9 @@ 
 #define   GEN7_SINGLE_SUBSCAN_DISPATCH_ENABLE	(1<<10)
 #define   GEN7_PSD_SINGLE_PORT_DISPATCH_ENABLE	(1<<3)
 
+#define GEN8_ROW_CHICKEN		0xe4f0
+#define   PARTIAL_INSTRUCTION_SHOOTDOWN_DISABLE	(1<<8)
+
 #define GEN7_ROW_CHICKEN2		0xe4f4
 #define GEN7_ROW_CHICKEN2_GT2		0xf4f4
 #define   DOP_CLOCK_GATING_DISABLE	(1<<0)
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 6273bc8f..169da9a 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -4803,6 +4803,10 @@  static void gen8_init_clock_gating(struct drm_device *dev)
 	/* FIXME(BDW): Check all the w/a, some might only apply to
 	 * pre-production hw. */
 
+	/* WaDisablePartialInstShootdown:bdw */
+	I915_WRITE(GEN8_ROW_CHICKEN,
+		   _MASKED_BIT_ENABLE(PARTIAL_INSTRUCTION_SHOOTDOWN_DISABLE));
+
 	/*
 	 * This GEN8_CENTROID_PIXEL_OPT_DIS W/A is only needed for
 	 * pre-production hardware