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| author | Tomoya MORINAGA <tomoya.rohm@gmail.com> | 2012-04-12 05:47:50 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-04-19 02:19:50 +0400 |
| commit | af6d17cdc8c89aeb3101f0d27cd32fc0592b40b2 (patch) | |
| tree | 588d1835847ccec5009c9ab744ca6a2de554bce7 | |
| parent | 7a6fbc9a887193a1e9f8658703881c528040afbc (diff) | |
| download | linux-af6d17cdc8c89aeb3101f0d27cd32fc0592b40b2.tar.xz | |
pch_uart: Fix dma channel unallocated issue
This driver anticipates pch_uart_verify_port() is not called
during installation.
However, actually pch_uart_verify_port() is called during
installation.
As a result, memory access violation occurs like below.
0. initial value: use_dma=0
1. starup()
- dma channel is not allocated because use_dma=0
2. pch_uart_verify_port()
- Set use_dma=1
3. UART processing acts DMA mode because use_dma=1
- memory access violation occurs!
This patch fixes the issue.
Solution:
Whenever pch_uart_verify_port() is called and then
dma channel is not allocated, the channel should be allocated.
Signed-off-by: Tomoya MORINAGA <tomoya.rohm@gmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/tty/serial/pch_uart.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c index bbbec4a74cfb..c2816f494807 100644 --- a/drivers/tty/serial/pch_uart.c +++ b/drivers/tty/serial/pch_uart.c @@ -1447,9 +1447,11 @@ static int pch_uart_verify_port(struct uart_port *port, __func__); return -EOPNOTSUPP; #endif - priv->use_dma = 1; priv->use_dma_flag = 1; dev_info(priv->port.dev, "PCH UART : Use DMA Mode\n"); + if (!priv->use_dma) + pch_request_dma(port); + priv->use_dma = 1; } return 0; |