if the DMA driver isn't loaded "on time" then we crash in the irq handler:
| pch_uart 0000:02:0a.4: pch_request_dma:dma_request_channel FAILS(Tx)
| BUG: unable to handle kernel NULL pointer dereference at (null)
| IP: [<c0676ed9>] pch_uart_interrupt+0x739/0x940
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
---
drivers/tty/serial/pch_uart.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c
index 20e4c94..9b7cd40 100644
--- a/drivers/tty/serial/pch_uart.c
+++ b/drivers/tty/serial/pch_uart.c
@@ -1492,10 +1492,14 @@ static int pch_uart_verify_port(struct uart_port *port,
__func__);
return -EOPNOTSUPP;
#endif
- dev_info(priv->port.dev, "PCH UART : Use DMA Mode\n");
- if (!priv->use_dma)
+ if (!priv->use_dma) {
pch_request_dma(port);
- priv->use_dma = 1;
+ if (priv->chan_rx)
+ priv->use_dma = 1;
+ }
+ dev_info(priv->port.dev, "PCH UART: %s\n",
+ priv->use_dma ?
+ "Use DMA Mode" : "No DMA");
}
return 0;
--
1.8.4.4
--
To unsubscribe from this list: send the line "unsubscribe linux-serial" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
