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serial: 8250_dma: power off device after TX is done 

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@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Andy Shevchenko 2016-11-14 12:26:52 +02:00 committed by Greg Kroah-Hartman
parent 7d4e00c625
commit 5fe8667484
1 changed files with 7 additions and 2 deletions
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9
drivers/tty/serial/8250/8250_dma.c
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@ -72,10 +72,15 @@ int serial8250_tx_dma(struct uart_8250_port *p)
struct dma_async_tx_descriptor *desc; struct dma_async_tx_descriptor *desc;
int ret; int ret;
if (uart_tx_stopped(&p->port) || dma->tx_running || if (dma->tx_running)
uart_circ_empty(xmit))
return 0; 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); dma->tx_size = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
desc = dmaengine_prep_slave_single(dma->txchan, desc = dmaengine_prep_slave_single(dma->txchan,