8250_core: Fix unwanted TX chars write
On transmit-hold-register empty, serial8250_tx_chars
should be called only if we don't use DMA.
DMA has its own tx cycle.
Signed-off-by: Loic Poulain <loic.poulain@intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index 81f909c..0e1bf88 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -1520,7 +1520,7 @@
status = serial8250_rx_chars(up, status);
}
serial8250_modem_status(up);
- if (status & UART_LSR_THRE)
+ if (!up->dma && (status & UART_LSR_THRE))
serial8250_tx_chars(up);
spin_unlock_irqrestore(&port->lock, flags);