FROMLIST: media: iris: Improve last flag handling

Improve the handling of the V4L2_BUF_FLAG_LAST flag in the driver:
- Ensure that the last flag is not sent multiple times.
- Attach the last flag to the first capture buffer returned during
  flush, triggered by a sequence change, addressing cases where the
  firmware does not set the last flag.

Link: https://lore.kernel.org/linux-arm-msm/20250509-video-iris-hevc-vp9-v5-19-59b4ff7d331c@quicinc.com/
Reviewed-by: Vikash Garodia <quic_vgarodia@quicinc.com>
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8550-QRD
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8550-HDK
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8650-QRD
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8650-HDK
Tested-by: Vikash Garodia <quic_vgarodia@quicinc.com> # on sa8775p-ride
Signed-off-by: Dikshita Agarwal <quic_dikshita@quicinc.com>

Author: Dikshita Agarwal

drivers/media/platform/qcom/iris/iris_buffer.c

@@ -636,6 +636,7 @@ int iris_vb2_buffer_done(struct iris_inst *inst, struct iris_buffer *buf)
 			v4l2_event_queue_fh(&inst->fh, &ev);
 			v4l2_m2m_mark_stopped(m2m_ctx);
 		}
+		inst->last_buffer_dequeued = true;
 	}
 
 	state = VB2_BUF_STATE_DONE;

drivers/media/platform/qcom/iris/iris_hfi_gen1_response.c

@@ -457,7 +457,12 @@ static void iris_hfi_gen1_session_ftb_done(struct iris_inst *inst, void *packet)
 		timestamp_us = timestamp_hi;
 		timestamp_us = (timestamp_us << 32) | timestamp_lo;
 	} else {
-		flags |= V4L2_BUF_FLAG_LAST;
+		if (pkt->stream_id == 1 && !inst->last_buffer_dequeued) {
+			if (iris_drc_pending(inst)) {
+				flags |= V4L2_BUF_FLAG_LAST;
+				inst->last_buffer_dequeued = true;
+			}
+		}
 	}
 	buf->timestamp = timestamp_us;
 

drivers/media/platform/qcom/iris/iris_instance.h

@@ -43,6 +43,7 @@
  * @sequence_out: a sequence counter for output queue
  * @tss: timestamp metadata
  * @metadata_idx: index for metadata buffer
+ * @last_buffer_dequeued: a flag to indicate that last buffer is sent by driver
  */
 
 struct iris_inst {
@@ -74,6 +75,7 @@ struct iris_inst {
 	u32				sequence_out;
 	struct iris_ts_metadata		tss[VIDEO_MAX_FRAME];
 	u32				metadata_idx;
+	bool				last_buffer_dequeued;
 };
 
 #endif

drivers/media/platform/qcom/iris/iris_vb2.c

@@ -305,7 +305,7 @@ void iris_vb2_buf_queue(struct vb2_buffer *vb2)
 		goto exit;
 	}
 
-	if (V4L2_TYPE_IS_CAPTURE(vb2->vb2_queue->type)) {
+	if (!inst->last_buffer_dequeued && V4L2_TYPE_IS_CAPTURE(vb2->vb2_queue->type)) {
 		if ((inst->sub_state & IRIS_INST_SUB_DRC &&
 		     inst->sub_state & IRIS_INST_SUB_DRC_LAST) ||
 		    (inst->sub_state & IRIS_INST_SUB_DRAIN &&
@@ -319,6 +319,7 @@ void iris_vb2_buf_queue(struct vb2_buffer *vb2)
 				v4l2_event_queue_fh(&inst->fh, &eos);
 				v4l2_m2m_mark_stopped(m2m_ctx);
 			}
+			inst->last_buffer_dequeued = true;
 			goto exit;
 		}
 	}

drivers/media/platform/qcom/iris/iris_vdec.c

@@ -487,6 +487,8 @@ static int iris_vdec_process_streamon_output(struct iris_inst *inst)
 	if (ret)
 		return ret;
 
+	inst->last_buffer_dequeued = false;
+
 	return iris_inst_change_sub_state(inst, clear_sub_state, 0);
 }