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| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2013-12-04 20:52:49 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-12-08 17:16:05 -0800 |
| commit | e41c0981213f39ecd421d8c1f7334cf04c2122e3 (patch) | |
| tree | c29c189f59e04cd6ca0d2c5a9df8c5554c1287ec /drivers/tty/serial/pch_uart.c | |
| parent | 0da3336f19f2a42e9153efa4112d50fd148a8e61 (diff) | |
| download | linux-e41c0981213f39ecd421d8c1f7334cf04c2122e3.tar.gz linux-e41c0981213f39ecd421d8c1f7334cf04c2122e3.tar.bz2 linux-e41c0981213f39ecd421d8c1f7334cf04c2122e3.zip | |
tty: serial: pch: don't crash if DMA enabled but not loaded
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@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/serial/pch_uart.c')
| -rw-r--r-- | drivers/tty/serial/pch_uart.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c index 0aa2b528ef3d..6bb7e90c8f22 100644 --- a/drivers/tty/serial/pch_uart.c +++ b/drivers/tty/serial/pch_uart.c @@ -1508,10 +1508,14 @@ 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; |