drm/i915/gen8: Add WaFlushCoherentL3CacheLinesAtContextSwitch workaround
In Indirect context w/a batch buffer,
+WaFlushCoherentL3CacheLinesAtContextSwitch:bdw
v2: Add LRI commands to set/reset bit that invalidates coherent lines,
update WA to include programming restrictions and exclude CHV as
it is not required (Ville)
v3: Avoid unnecessary read when it can be done by reading register once (Chris).
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Dave Gordon <david.s.gordon@intel.com>
Signed-off-by: Rafael Barbalho <rafael.barbalho@intel.com>
Signed-off-by: Arun Siluvery <arun.siluvery@linux.intel.com>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index a1198ba..2b65d29 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1143,6 +1143,29 @@
/* WaDisableCtxRestoreArbitration:bdw,chv */
wa_ctx_emit(batch, MI_ARB_ON_OFF | MI_ARB_DISABLE);
+ /* WaFlushCoherentL3CacheLinesAtContextSwitch:bdw */
+ if (IS_BROADWELL(ring->dev)) {
+ struct drm_i915_private *dev_priv = to_i915(ring->dev);
+ uint32_t l3sqc4_flush = (I915_READ(GEN8_L3SQCREG4) |
+ GEN8_LQSC_FLUSH_COHERENT_LINES);
+
+ wa_ctx_emit(batch, MI_LOAD_REGISTER_IMM(1));
+ wa_ctx_emit(batch, GEN8_L3SQCREG4);
+ wa_ctx_emit(batch, l3sqc4_flush);
+
+ wa_ctx_emit(batch, GFX_OP_PIPE_CONTROL(6));
+ wa_ctx_emit(batch, (PIPE_CONTROL_CS_STALL |
+ PIPE_CONTROL_DC_FLUSH_ENABLE));
+ wa_ctx_emit(batch, 0);
+ wa_ctx_emit(batch, 0);
+ wa_ctx_emit(batch, 0);
+ wa_ctx_emit(batch, 0);
+
+ wa_ctx_emit(batch, MI_LOAD_REGISTER_IMM(1));
+ wa_ctx_emit(batch, GEN8_L3SQCREG4);
+ wa_ctx_emit(batch, l3sqc4_flush & ~GEN8_LQSC_FLUSH_COHERENT_LINES);
+ }
+
/* Pad to end of cacheline */
while (index % CACHELINE_DWORDS)
wa_ctx_emit(batch, MI_NOOP);