The patch titled
atmel_serial-might-lose-modem-status-change fix
has been removed from the -mm tree. Its filename was
atmel_serial-might-lose-modem-status-change-fix.patch
This patch was dropped because an updated version will be merged
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: atmel_serial-might-lose-modem-status-change fix
From: Haavard Skinnemoen <haavard.skinnemoen@xxxxxxxxx>
...Itai Levi pointed out that we need to initialize
atmel_port->irq_status as well here. His analysis is as follows:
> Regarding the second part of the patch (which resets irq_status_prev),
> it turns out that both versions of the patch (mine and Atsushi's)
> still leave enough room for faulty behavior when opening the port.
>
> This is because we are not resetting both irq_status_prev and
> irq_status in atmel_startup() to CSR, which leads faulty behavior in
> the following sequences:
>
> First case:
> 1. closing the port while CTS line = 1 (TX not allowed)
> 2. setting CTS line = 0 (TX allowed)
> 3. opening the port
> 4. transmitting one char
> 5. Cannot transmit more chars, although CTS line is 0
>
> Second case:
> 1. closing the port while CTS line = 0 (TX allowed)
> 2. setting CTS line = 1 (TX not allowed)
> 3. opening the port
> 4. receiving some chars
> 5. Now we can transmit, although CTS line is 1
>
> This reason for this is that the tasklet is scheduled as a result of
> TX or RX interrupts (not a status change!), in steps 4 above. Inside
> the tasklet, the atmel_port->irq_status (which holds the value from
> the previous session) is compared to atmel_port->irq_status_prev.
> Hence, a status-change of the CTS line is faultily detected.
>
> Both cases were verified on 9260 hardware.
>
> The solution for this, is to reset both irq_status_prev and irq_status
> to the value of CSR in atmel_startup().
>
> Here is my updated patch (you can ignore the first part which you
> already accepted):
Cc: Atsushi Nemoto <anemo@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/serial/atmel_serial.c | 3 +++
1 file changed, 3 insertions(+)
diff -puN drivers/serial/atmel_serial.c~atmel_serial-might-lose-modem-status-change-fix drivers/serial/atmel_serial.c
--- a/drivers/serial/atmel_serial.c~atmel_serial-might-lose-modem-status-change-fix
+++ a/drivers/serial/atmel_serial.c
@@ -805,6 +805,9 @@ static int atmel_startup(struct uart_por
*/
UART_PUT_IDR(port, -1);
+ atmel_port->irq_status_prev = UART_GET_CSR(port);
+ atmel_port->irq_status = atmel_port->irq_status_prev;
+
/*
* Allocate the IRQ
*/
_
Patches currently in -mm which might be from haavard.skinnemoen@xxxxxxxxx are
atmel_serial-fix-flow-control-bug.patch
atmel_spi-allow-transfer-when-max_speed_hz-=-0.patch
atmel_serial-might-lose-modem-status-change-fix.patch
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