[Intel-gfx] [PATCH 2/2] drm/i915/gen9: Add WaDisableGatherAtSetShaderCommonSlice

[Mika Kuoppala]

From: Mika Kuoppala <mika.kuoppala at linux.intel.com>

Add WaDisableGatherAtSetShaderCommonSlice for all gen9 as stated
by bspec. The bspec told to put this workaround to the per ctx bb.
Initial implementation and subsequent review were done based on
bspec. Arun raised a suspicion that this would belong to indirect bb
instead and he conducted more throughout investigation on the matter
and indeed the documentation was wrong.

v2: Move to indirect_ctx wa bb, as it is correct place (Arun)

References: HSD#2135817
Cc: Arun Siluvery <arun.siluvery at linux.intel.com>
Cc: Matthew Auld <matthew.auld at intel.com>
Signed-off-by: Mika Kuoppala <mika.kuoppala at intel.com>
Reviewed-by: Matthew Auld <matthew.auld at intel.com> (v1)
Reviewed-by: Arun Siluvery <arun.siluvery at linux.intel.com>
---
 drivers/gpu/drm/i915/i915_reg.h  | 1 +
 drivers/gpu/drm/i915/intel_lrc.c | 7 +++++++
 2 files changed, 8 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index ce14fe09d962..f031231e89e6 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -6132,6 +6132,7 @@ enum {
 # define GEN7_CSC1_RHWO_OPT_DISABLE_IN_RCC	((1<<10) | (1<<26))
 # define GEN9_RHWO_OPTIMIZATION_DISABLE		(1<<14)
 #define COMMON_SLICE_CHICKEN2			_MMIO(0x7014)
+# define GEN9_DISABLE_GATHER_AT_SET_SHADER_COMMON_SLICE (1<<12)
 # define GEN8_SBE_DISABLE_REPLAY_BUF_OPTIMIZATION (1<<8)
 # define GEN8_CSC2_SBE_VUE_CACHE_CONSERVATIVE	(1<<0)
 
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 860dba2cf7b3..afd76591bbb8 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1256,6 +1256,13 @@ static int gen9_init_indirectctx_bb(struct intel_engine_cs *engine,
 		return ret;
 	index = ret;
 
+	/* WaDisableGatherAtSetShaderCommonSlice:skl,bxt,kbl */
+	wa_ctx_emit(batch, index, MI_LOAD_REGISTER_IMM(1));
+	wa_ctx_emit_reg(batch, index, COMMON_SLICE_CHICKEN2);
+	wa_ctx_emit(batch, index, _MASKED_BIT_DISABLE(
+			    GEN9_DISABLE_GATHER_AT_SET_SHADER_COMMON_SLICE));
+	wa_ctx_emit(batch, index, MI_NOOP);
+
 	/* WaClearSlmSpaceAtContextSwitch:kbl */
 	/* Actual scratch location is at 128 bytes offset */
 	if (IS_KBL_REVID(engine->i915, 0, KBL_REVID_A0)) {
-- 
2.7.4