drm/i915/gen9: Add WaDisableCtxRestoreArbitration workaround

In Indirect and Per context w/a batch buffer,
+WaDisableCtxRestoreArbitration

v2: SKL revision id was used for BXT, copy paste error found during
internal review (Bob Beckett).

v3: use updated macro.
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Robert Beckett <robert.beckett@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Signed-off-by: Arun Siluvery <arun.siluvery@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_lrc.c

@@ -1253,10 +1253,13 @@ static int gen9_init_indirectctx_bb(struct intel_engine_cs *ring,
 				    uint32_t *const batch,
 				    uint32_t *offset)
 {
+	struct drm_device *dev = ring->dev;
 	uint32_t index = wa_ctx_start(wa_ctx, *offset, CACHELINE_DWORDS);
 
-	/* FIXME: Replace me with WA */
-	wa_ctx_emit(batch, index, MI_NOOP);
+	/* WaDisableCtxRestoreArbitration:skl,bxt */
+	if ((IS_SKYLAKE(dev) && (INTEL_REVID(dev) <= SKL_REVID_D0)) ||
+	    (IS_BROXTON(dev) && (INTEL_REVID(dev) == BXT_REVID_A0)))
+		wa_ctx_emit(batch, index, MI_ARB_ON_OFF | MI_ARB_DISABLE);
 
 	/* Pad to end of cacheline */
 	while (index % CACHELINE_DWORDS)
@@ -1270,8 +1273,14 @@ static int gen9_init_perctx_bb(struct intel_engine_cs *ring,
 			       uint32_t *const batch,
 			       uint32_t *offset)
 {
+	struct drm_device *dev = ring->dev;
 	uint32_t index = wa_ctx_start(wa_ctx, *offset, CACHELINE_DWORDS);
 
+	/* WaDisableCtxRestoreArbitration:skl,bxt */
+	if ((IS_SKYLAKE(dev) && (INTEL_REVID(dev) <= SKL_REVID_D0)) ||
+	    (IS_BROXTON(dev) && (INTEL_REVID(dev) == BXT_REVID_A0)))
+		wa_ctx_emit(batch, index, MI_ARB_ON_OFF | MI_ARB_ENABLE);
+
 	wa_ctx_emit(batch, index, MI_BATCH_BUFFER_END);
 
 	return wa_ctx_end(wa_ctx, *offset = index, 1);