When any 8250 based driver sets up DMA and has UART_CAP_RPM capability enabled
the device is left powered on after transfer is done. We need to schedule a
device suspend operation when DMA completes the transfer.
The patch is based on the work done by the reporter.
Reported-by: Huiquan Zhong <huiquan.zhong@xxxxxxxxx>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
drivers/tty/serial/8250/8250_dma.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c
index fdbddbc..7e94e05 100644
--- a/drivers/tty/serial/8250/8250_dma.c
+++ b/drivers/tty/serial/8250/8250_dma.c
@@ -76,6 +76,12 @@ int serial8250_tx_dma(struct uart_8250_port *p)
uart_circ_empty(xmit))
return 0;
+ if (uart_tx_stopped(&p->port) || uart_circ_empty(xmit)) {
+ /* We have been called from __dma_tx_complete() */
+ serial8250_rpm_put_tx(p);
+ return 0;
+ }
+
dma->tx_size = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
desc = dmaengine_prep_slave_single(dma->txchan,
--
2.9.3
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