Commit 5fe86674 authored Nov 14, 2016 by Andy Shevchenko Committed by Greg Kroah-Hartman Nov 16, 2016

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>

parent 7d4e00c6

drivers/tty/serial/8250/8250_dma.c

+7 −2

Original line number	Diff line number	Diff line
		@@ -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,