Quoting Michał Winiarski (2017-09-14 09:32:15) > @@ -434,11 +432,12 @@ static void guc_wq_item_append(struct i915_guc_client *client, > */ > BUILD_BUG_ON(wqi_size != 16); > > - /* postincrement WQ tail for next time */ > - wq_off = client->wq_tail; > + /* Postincrement WQ tail for next time, free space is guaranteed. */ > + wq_off = READ_ONCE(desc->tail); > + GEM_BUG_ON(CIRC_SPACE(wq_off, READ_ONCE(desc->head), > + GUC_WQ_SIZE) < wqi_size); > + WRITE_ONCE(desc->tail, (wq_off + wqi_size) & (GUC_WQ_SIZE - 1)); > GEM_BUG_ON(wq_off & (wqi_size - 1)); > - client->wq_tail += wqi_size; > - client->wq_tail &= client->wq_size - 1; > > /* WQ starts from the page after doorbell / process_desc */ > wqi = client->vaddr + wq_off + GUC_DB_SIZE; > @@ -451,7 +450,7 @@ static void guc_wq_item_append(struct i915_guc_client *client, > > wqi->context_desc = lower_32_bits(intel_lr_context_descriptor(ctx, engine)); > > - wqi->submit_element_info = tail << WQ_RING_TAIL_SHIFT; > + wqi->submit_element_info = ring_tail << WQ_RING_TAIL_SHIFT; > wqi->fence_id = rq->global_seqno; Ah, you reminded me that we should set the wq element before updating the tail, i.e. move the WRITE_ONCE(desc->tail, (wq_off + wqi_size) & (GUC_WQ_SIZE - 1)); to here. -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
