diff mbox

[10/10] DONT_MERGE drm/i915: FORCE_RESTORE for gen8 semaphores

Message ID 1399483626-7540-11-git-send-email-benjamin.widawsky@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Ben Widawsky May 7, 2014, 5:27 p.m. UTC 
This appears to not actually be needed on the current code. Just putting
it on the ML so we can point bug reports at it later.

As pointed out by Ville, the current code is "broken" since we do
FORCE_RESTORE, and RESTORE_INHIBIT on the same dword. Anecdotally, this
seems fine.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
---
 drivers/gpu/drm/i915/i915_gem_context.c | 7 +++++++
 1 file changed, 7 insertions(+)
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index f77b4c1..aa82fb4 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -661,6 +661,13 @@  static int do_switch(struct intel_ring_buffer *ring,
 	if (!to->is_initialized || i915_gem_context_is_default(to))
 		hw_flags |= MI_RESTORE_INHIBIT;
 
+	/* When SW intends to use semaphore signaling between Command streamers,
+	 * it must avoid lite restores in HW by programming "Force Restore" bit
+	 * to ‘1’ in context descriptor during context submission
+	 */
+	if (IS_GEN8(ring->dev) && i915_semaphore_is_enabled(ring->dev))
+		hw_flags |= MI_FORCE_RESTORE;
+
 	ret = mi_set_context(ring, to, hw_flags);
 	if (ret)
 		goto unpin_out;