[Intel-gfx] [PATCH v2 5/7] drm/i915/gen8: Add WaFlushCoherentL3CacheLinesAtContextSwitch workaround

[Arun Siluvery]

In Indirect context w/a batch buffer,
+WaFlushCoherentL3CacheLinesAtContextSwitch

Signed-off-by: Rafael Barbalho <rafael.barbalho at intel.com>
Signed-off-by: Arun Siluvery <arun.siluvery at linux.intel.com>
---
 drivers/gpu/drm/i915/i915_reg.h  | 1 +
 drivers/gpu/drm/i915/intel_lrc.c | 8 ++++++++
 2 files changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 84af255..5203c79 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -426,6 +426,7 @@
 #define   PIPE_CONTROL_INDIRECT_STATE_DISABLE		(1<<9)
 #define   PIPE_CONTROL_NOTIFY				(1<<8)
 #define   PIPE_CONTROL_FLUSH_ENABLE			(1<<7) /* gen7+ */
+#define   PIPE_CONTROL_DC_FLUSH_ENABLE			(1<<5)
 #define   PIPE_CONTROL_VF_CACHE_INVALIDATE		(1<<4)
 #define   PIPE_CONTROL_CONST_CACHE_INVALIDATE		(1<<3)
 #define   PIPE_CONTROL_STATE_CACHE_INVALIDATE		(1<<2)
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 8ed6433..24a7dcd 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1132,6 +1132,14 @@ static int gen8_init_indirectctx_bb(struct intel_engine_cs *ring,
 	/* WaDisableCtxRestoreArbitration:bdw,chv */
 	intel_logical_ring_emit(ringbuf, MI_ARB_ON_OFF | MI_ARB_DISABLE);
 
+	/* WaFlushCoherentL3CacheLinesAtContextSwitch:bdw,chv */
+	intel_logical_ring_emit(ringbuf, GFX_OP_PIPE_CONTROL(6));
+	intel_logical_ring_emit(ringbuf, PIPE_CONTROL_DC_FLUSH_ENABLE);
+	intel_logical_ring_emit(ringbuf, 0);
+	intel_logical_ring_emit(ringbuf, 0);
+	intel_logical_ring_emit(ringbuf, 0);
+	intel_logical_ring_emit(ringbuf, 0);
+
 	/* padding */
 	while (((unsigned long) ringbuf->tail % CACHELINE_BYTES) != 0)
 		intel_logical_ring_emit(ringbuf, MI_NOOP);
-- 
2.3.0