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authorAndy Green <andy.green@txtr.com>2010-02-01 13:28:54 +0100
committerSascha Hauer <s.hauer@pengutronix.de>2010-02-16 17:16:47 +0100
commit94d32f99c6aba8b702a9cf78cb328aeb7882b1e5 (patch)
treea3544b4959da6e325c11d9cd568b07bdd4c0a94c /drivers/serial/imx.c
parente335c75cf32b7014f84c90bbe7ed9b7ecd8e7778 (diff)
imx-serial-excessive-status-clearing-on-break.patch
cc: Sasha Hauer <kernel@pengutronix.de> We noticed that we were only able to communicate once with a GSM module per session, if we powered down the module then the serial driver was broken until reset, no traffic or /proc/interrupts activity could be seen any more. Volker noticed it was provoked by a long "break" seen on the wire when the RX was not driven during powerdown, we discovered we could kill the serial driver just by forcing RX low extenally for a little while. I saw that the processing for BREAK in the driver gets too excited and clears down all set bits in USR2, including that a character is pending. This stops all further characters getting processed. The attached one-liner makes the serial driver immortal against BREAK. Signed-off-by: Andy Green <andy.green@txtr.com> Signed-off-by: Volker Ernst <volker.ernst@txtr.com> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'drivers/serial/imx.c')
-rw-r--r--drivers/serial/imx.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/serial/imx.c b/drivers/serial/imx.c
index 18130f11238..c5b546a9852 100644
--- a/drivers/serial/imx.c
+++ b/drivers/serial/imx.c
@@ -440,7 +440,7 @@ static irqreturn_t imx_rxint(int irq, void *dev_id)
temp = readl(sport->port.membase + USR2);
if (temp & USR2_BRCD) {
- writel(temp | USR2_BRCD, sport->port.membase + USR2);
+ writel(USR2_BRCD, sport->port.membase + USR2);
if (uart_handle_break(&sport->port))
continue;
}