media: venus: preserve DRC state across seeks

DRC events can happen virtually at anytime, including when we are
starting a seek. Should this happen, we must make sure to return to the
DRC state, otherwise the firmware will expect buffers of the new
resolution whereas userspace will still work with the old one.

Returning to the DRC state upon resume for seeking makes sure that the
client will get the DRC event and will reallocate the buffers to fit the
firmware's expectations.
Signed-off-by: Alexandre Courbot <acourbot@chromium.org>
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/platform/qcom/venus/vdec.c

@@ -988,7 +988,10 @@ static int vdec_start_output(struct venus_inst *inst)
 
 	if (inst->codec_state == VENUS_DEC_STATE_SEEK) {
 		ret = venus_helper_process_initial_out_bufs(inst);
-		inst->codec_state = VENUS_DEC_STATE_DECODING;
+		if (inst->next_buf_last)
+			inst->codec_state = VENUS_DEC_STATE_DRC;
+		else
+			inst->codec_state = VENUS_DEC_STATE_DECODING;
 		goto done;
 	}
 
@@ -1094,8 +1097,10 @@ static int vdec_stop_capture(struct venus_inst *inst)
 		ret = hfi_session_flush(inst, HFI_FLUSH_ALL, true);
 		fallthrough;
 	case VENUS_DEC_STATE_DRAIN:
-		vdec_cancel_dst_buffers(inst);
 		inst->codec_state = VENUS_DEC_STATE_STOPPED;
+		fallthrough;
+	case VENUS_DEC_STATE_SEEK:
+		vdec_cancel_dst_buffers(inst);
 		break;
 	case VENUS_DEC_STATE_DRC:
 		ret = hfi_session_flush(inst, HFI_FLUSH_OUTPUT, true);
@@ -1117,6 +1122,7 @@ static int vdec_stop_output(struct venus_inst *inst)
 	case VENUS_DEC_STATE_DECODING:
 	case VENUS_DEC_STATE_DRAIN:
 	case VENUS_DEC_STATE_STOPPED:
+	case VENUS_DEC_STATE_DRC:
 		ret = hfi_session_flush(inst, HFI_FLUSH_ALL, true);
 		inst->codec_state = VENUS_DEC_STATE_SEEK;
 		break;
@@ -1390,6 +1396,7 @@ static void vdec_event_change(struct venus_inst *inst,
 			dev_dbg(dev, VDBGH "flush output error %d\n", ret);
 	}
 
+	inst->next_buf_last = true;
 	inst->reconfig = true;
 	v4l2_event_queue_fh(&inst->fh, &ev);
 	wake_up(&inst->reconf_wait);