[Intel-gfx] [PATCH] drm/i915/skl: Fix WaDisableChickenBitTSGBarrierAckForFFSliceCS

[Damien Lespiau]

Robert noticed that the FF_SLICE_CS_CHICKEN2 offset was wrong. Ooops.

Ville noticed that the write was wrong since FF_SLICE_CS_CHICKEN2 is a
masked register. Re-oops.

A wonder if went through 2 people while having roughly a bug per line...

The problem was introduced in the original patch:

  commit 2caa3b260aa6a3d015352c07d1bce1461825fa6c
  Author: Damien Lespiau <damien.lespiau at intel.com>
  Date:   Mon Feb 9 19:33:20 2015 +0000

      drm/i915/skl: Implement WaDisableChickenBitTSGBarrierAckForFFSliceCS

v2: Also fix the register write (Ville)

Reported-by: Robert Beckett <robert.beckett at intel.com>
Reported-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
Cc: Robert Beckett <robert.beckett at intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Cc: Nick Hoath <nicholas.hoath at intel.com>

Signed-off-by: Damien Lespiau <damien.lespiau at intel.com>
---
 drivers/gpu/drm/i915/i915_reg.h | 2 +-
 drivers/gpu/drm/i915/intel_pm.c | 3 +--
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 5436ab0..6a1875a 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -5718,7 +5718,7 @@ enum skl_disp_power_wells {
 #define HSW_NDE_RSTWRN_OPT	0x46408
 #define  RESET_PCH_HANDSHAKE_ENABLE	(1<<4)
 
-#define FF_SLICE_CS_CHICKEN2			0x02e4
+#define FF_SLICE_CS_CHICKEN2			0x20e4
 #define  GEN9_TSG_BARRIER_ACK_DISABLE		(1<<8)
 
 /* GEN7 chicken */
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 8812fff..e940a28 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -88,8 +88,7 @@ static void skl_init_clock_gating(struct drm_device *dev)
 
 		/* WaDisableChickenBitTSGBarrierAckForFFSliceCS:skl */
 		I915_WRITE(FF_SLICE_CS_CHICKEN2,
-			   I915_READ(FF_SLICE_CS_CHICKEN2) |
-			   GEN9_TSG_BARRIER_ACK_DISABLE);
+			   _MASKED_BIT_ENABLE(GEN9_TSG_BARRIER_ACK_DISABLE));
 	}
 
 	if (INTEL_REVID(dev) <= SKL_REVID_E0)
-- 
2.1.0