diff options
| author | Andy Green <andy.green@txtr.com> | 2010-02-01 13:28:54 +0100 |
|---|---|---|
| committer | Sascha Hauer <s.hauer@pengutronix.de> | 2010-02-16 17:16:47 +0100 |
| commit | 94d32f99c6aba8b702a9cf78cb328aeb7882b1e5 (patch) | |
| tree | a3544b4959da6e325c11d9cd568b07bdd4c0a94c /drivers | |
| parent | e335c75cf32b7014f84c90bbe7ed9b7ecd8e7778 (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')
| -rw-r--r-- | drivers/serial/imx.c | 2 |
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; } |