drm/i915/execlists: Flush the post-sync breadcrumb write harder

Quite rarely we see that the CS completion event fires before the
breadcrumb is coherent, which presumably is a result of the CS_STALL not
waiting for the post-sync operation. Try throwing in a DC_FLUSH into
the following pipecontrol to see if that makes any difference.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Acked-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190827120615.31390-1-chris@chris-wilson.co.uk
This commit is contained in:
Chris Wilson 2019-08-27 13:06:15 +01:00
parent c4e6488120
commit e8f6b4952e

View File

@ -2923,8 +2923,10 @@ static u32 *gen8_emit_fini_breadcrumb_rcs(struct i915_request *request, u32 *cs)
PIPE_CONTROL_DC_FLUSH_ENABLE);
/* XXX flush+write+CS_STALL all in one upsets gem_concurrent_blt:kbl */
/* XXX DC_FLUSH for post-sync write? (cf early context-switch bug) */
cs = gen8_emit_pipe_control(cs,
PIPE_CONTROL_FLUSH_ENABLE |
PIPE_CONTROL_DC_FLUSH_ENABLE |
PIPE_CONTROL_CS_STALL,
0);