drm/i915/execlists: Remove the ring advancement under preemption

Load an empty ringbuffer for preemption, ignoring the lite-restore
workaround as we know the preempt context is always idle before preemption.

Note that after some digging by Michal Winiarski, we found that
RING_HEAD is no longer being updated (due to inhibiting context save
restore) so this patch is already in effect!

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michal Winiarski <michal.winiarski@intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Michel Thierry <michel.thierry@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180221133236.29402-1-chris@chris-wilson.co.uk
This commit is contained in:
Chris Wilson 2018-02-21 13:32:36 +00:00
parent e61e0f51ba
commit 561210706c

View file

@ -447,13 +447,6 @@ static void inject_preempt_context(struct intel_engine_cs *engine)
GEM_BUG_ON(engine->execlists.preempt_complete_status !=
upper_32_bits(ce->lrc_desc));
GEM_BUG_ON(!IS_ALIGNED(ce->ring->size, WA_TAIL_BYTES));
memset(ce->ring->vaddr + ce->ring->tail, 0, WA_TAIL_BYTES);
ce->ring->tail += WA_TAIL_BYTES;
ce->ring->tail &= (ce->ring->size - 1);
ce->lrc_reg_state[CTX_RING_TAIL+1] = ce->ring->tail;
GEM_BUG_ON((ce->lrc_reg_state[CTX_CONTEXT_CONTROL + 1] &
_MASKED_BIT_ENABLE(CTX_CTRL_ENGINE_CTX_RESTORE_INHIBIT |
CTX_CTRL_ENGINE_CTX_SAVE_INHIBIT)) !=