[Intel-gfx] [PATCH] drm/i915/icl: restore WaEnableFloatBlendOptimization

[TalhaNassartalha.nassar at intel.com]

From: talha nassar <talha.nassar at intel.com>

Enables blend optimization for floating point RTs

This restores the workaround that was reverted in c358514ba8da
("Revert "drm/i915/icl: WaEnableFloatBlendOptimization"").

The revert was due to the register write seemingly not sticking,
but the HW team has confirmed that this is because the
register is WO and that the workaround is indeed required.

References: https://bugs.freedesktop.org/show_bug.cgi?id=107338
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
Signed-off-by: talha nassar <talha.nassar at intel.com>
---
 drivers/gpu/drm/i915/i915_reg.h          | 3 +++
 drivers/gpu/drm/i915/intel_workarounds.c | 4 ++++
 2 files changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 0796526..5c43720 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -2795,6 +2795,9 @@ enum i915_power_well_id {
 #define GEN6_RCS_PWR_FSM _MMIO(0x22ac)
 #define GEN9_RCS_FE_FSM2 _MMIO(0x22a4)
 
+#define GEN10_CACHE_MODE_SS			_MMIO(0xe420)
+#define   FLOAT_BLEND_OPTIMIZATION_ENABLE	(1 << 4)
+
 /* Fuse readout registers for GT */
 #define HSW_PAVP_FUSE1			_MMIO(0x911C)
 #define   HSW_F1_EU_DIS_SHIFT		16
diff --git a/drivers/gpu/drm/i915/intel_workarounds.c b/drivers/gpu/drm/i915/intel_workarounds.c
index 7a86180..bc614f0 100644
--- a/drivers/gpu/drm/i915/intel_workarounds.c
+++ b/drivers/gpu/drm/i915/intel_workarounds.c
@@ -532,6 +532,10 @@ static void icl_ctx_workarounds_init(struct intel_engine_cs *engine)
 	if (IS_ICL_REVID(i915, ICL_REVID_A0, ICL_REVID_A0))
 		WA_SET_BIT_MASKED(GEN11_COMMON_SLICE_CHICKEN3,
 				  GEN11_BLEND_EMB_FIX_DISABLE_IN_RCC);
+
+	/* WaEnableFloatBlendOptimization:icl */
+	WA_SET_BIT_MASKED(GEN10_CACHE_MODE_SS,
+			  FLOAT_BLEND_OPTIMIZATION_ENABLE);
 }
 
 void intel_engine_init_ctx_wa(struct intel_engine_cs *engine)
-- 
2.7.4