[PATCH v6 08/34] drm/i915: Force MMIO flips when scheduler enabled

John.C.Harrison
2016-04-20T17:14:06Z

MMIO flips are the preferred mechanism now but more importantly, pipe
based flips cause issues for the scheduler. Specifically, submitting
work to the rings around the side of the scheduler could cause that
work to be lost if the scheduler generates a pre-emption event on that
ring.

For: VIZ-1587
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
---
drivers/gpu/drm/i915/intel_display.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index e550e5b..9407934 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -47,6 +47,7 @@
#include <linux/dma_remapping.h>
#include <linux/reservation.h>
#include <linux/dma-buf.h>
+#include "i915_scheduler.h"

/* Primary plane formats for gen <= 3 */
static const uint32_t i8xx_primary_formats[] = {
@@ -11244,6 +11245,8 @@ static bool use_mmio_flip(struct intel_engine_cs *engine,
return true;
else if (i915.enable_execlists)
return true;
+ else if (i915_scheduler_is_enabled(engine->dev))
+ return true;
else if (obj->base.dma_buf &&
!reservation_object_test_signaled_rcu(obj->base.dma_buf->resv,
false))