This is a note to let you know that I've just added the patch titled
pch_uart: Fix dma channel unallocated issue
to my tty git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
in the tty-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also will be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From af6d17cdc8c89aeb3101f0d27cd32fc0592b40b2 Mon Sep 17 00:00:00 2001
From: Tomoya MORINAGA <[email protected]>
Date: Thu, 12 Apr 2012 10:47:50 +0900
Subject: 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 <[email protected]>
Cc: stable <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/tty/serial/pch_uart.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c
index bbbec4a..c2816f4 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;
--
1.7.10
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
