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 | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c
index fdbddbc..26f1745 100644
--- a/drivers/tty/serial/8250/8250_dma.c
+++ b/drivers/tty/serial/8250/8250_dma.c
@@ -72,10 +72,15 @@ int serial8250_tx_dma(struct uart_8250_port *p)
struct dma_async_tx_descriptor *desc;
int ret;
- if (uart_tx_stopped(&p->port) || dma->tx_running ||
- uart_circ_empty(xmit))
+ if (dma->tx_running)
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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