@@ -433,12 +433,6 @@ lrc_descriptor(struct intel_context *ce, struct intel_engine_cs *engine)
return desc;
}
-static void unwind_wa_tail(struct i915_request *rq)
-{
- rq->tail = intel_ring_wrap(rq->ring, rq->wa_tail - WA_TAIL_BYTES);
- assert_ring_tail_valid(rq->ring, rq->tail);
-}
-
static struct i915_request *
__unwind_incomplete_requests(struct intel_engine_cs *engine)
{
@@ -457,7 +451,6 @@ __unwind_incomplete_requests(struct intel_engine_cs *engine)
continue; /* XXX */
__i915_request_unsubmit(rq);
- unwind_wa_tail(rq);
/*
* Push the request back into the queue for later resubmission.
@@ -575,13 +568,29 @@ execlists_schedule_out(struct i915_request *rq)
i915_request_put(rq);
}
-static u64 execlists_update_context(const struct i915_request *rq)
+static u64 execlists_update_context(struct i915_request *rq)
{
struct intel_context *ce = rq->hw_context;
- u64 desc;
+ u64 desc = ce->lrc_desc;
+ u32 tail;
- ce->lrc_reg_state[CTX_RING_TAIL + 1] =
- intel_ring_set_tail(rq->ring, rq->tail);
+ /*
+ * WaIdleLiteRestore:bdw,skl
+ *
+ * We should never submit the context with the same RING_TAIL twice
+ * just in case we submit an empty ring, which confuses the HW.
+ *
+ * We append a couple of NOOPs (gen8_emit_wa_tail) after the end of
+ * the normal request to be able to always advance the RING_TAIL on
+ * subsequent resubmissions (for lite restore). Should that fail us,
+ * and we try and submit the same tail again, force the context
+ * reload.
+ */
+ tail = intel_ring_set_tail(rq->ring, rq->tail);
+ if (unlikely(ce->lrc_reg_state[CTX_RING_TAIL] == tail))
+ desc |= CTX_DESC_FORCE_RESTORE;
+ ce->lrc_reg_state[CTX_RING_TAIL] = tail;
+ rq->tail = rq->wa_tail;
/*
* Make sure the context image is complete before we submit it to HW.
@@ -600,9 +609,7 @@ static u64 execlists_update_context(const struct i915_request *rq)
*/
mb();
- desc = ce->lrc_desc;
ce->lrc_desc &= ~CTX_DESC_FORCE_RESTORE;
-
return desc;
}
@@ -936,16 +943,6 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
if (!list_is_last(&last->sched.link,
&engine->active.requests))
return;
-
- /*
- * WaIdleLiteRestore:bdw,skl
- * Apply the wa NOOPs to prevent
- * ring:HEAD == rq:TAIL as we resubmit the
- * request. See gen8_emit_fini_breadcrumb() for
- * where we prepare the padding after the
- * end of the request.
- */
- last->tail = last->wa_tail;
}
}