[Intel-gfx] [PATCH 2/4] drm/i915: gen7: Implement an L3 caching workaround.

[Kenneth Graunke]

From: Eugeni Dodonov <eugeni.dodonov at intel.com>

This adds two cache-related workarounds for Ivy Bridge which can lead to
3D ring hangs and corruptions.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=41353
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=44610
Tested-by: Eugeni Dodonov <eugeni.dodonov at intel.com>
Signed-off-by: Eugeni Dodonov <eugeni.dodonov at intel.com>
Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
---
 drivers/gpu/drm/i915/i915_reg.h      |    7 +++++++
 drivers/gpu/drm/i915/intel_display.c |    6 ++++++
 2 files changed, 13 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 80fd6b5..ca4737e 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -3028,6 +3028,13 @@
 #define  DISP_TILE_SURFACE_SWIZZLING	(1<<13)
 #define  DISP_FBC_WM_DIS		(1<<15)
 
+/* GEN7 chicken */
+#define GEN7_L3CNTLREG1				0xB01C
+#define  GEN7_WA_FOR_GEN7_L3_CONTROL			0x3C4FFF8C
+
+#define GEN7_L3_CHICKEN_MODE_REGISTER		0xB030
+#define  GEN7_WA_L3_CHICKEN_MODE				0x20000000
+
 /* PCH */
 
 /* south display engine interrupt */
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 070c946..2db1b67 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -8472,6 +8472,12 @@ static void ivybridge_init_clock_gating(struct drm_device *dev)
 		   CHICKEN3_DGMG_REQ_OUT_FIX_DISABLE |
 		   CHICKEN3_DGMG_DONE_FIX_DISABLE);
 
+	/* WaApplyL3ControlAndL3ChickenMode requires those two on Ivy Bridge */
+	I915_WRITE(GEN7_L3CNTLREG1,
+			GEN7_WA_FOR_GEN7_L3_CONTROL);
+	I915_WRITE(GEN7_L3_CHICKEN_MODE_REGISTER,
+			GEN7_WA_L3_CHICKEN_MODE);
+
 	for_each_pipe(pipe) {
 		I915_WRITE(DSPCNTR(pipe),
 			   I915_READ(DSPCNTR(pipe)) |
-- 
1.7.7.1