On 03/04/2019 17:02, Greg Kroah-Hartman wrote:
> On Tue, Apr 02, 2019 at 12:52:50PM +0300, Razvan Stefanescu wrote:
>> commit 69646d7a3689 ("tty/serial: atmel: RS485 HD w/DMA: enable RX after TX is stopped") upstream.
>>
>> In half-duplex operation, RX should be started after TX completes.
>>
>> If DMA is used, there is a case when the DMA transfer completes but the
>> TX FIFO is not emptied, so the RX cannot be restarted just yet.
>>
>> Use a boolean variable to store this state and rearm TX interrupt mask
>> to be signaled again that the transfer finished. In interrupt transmit
>> handler this variable is used to start RX. A warning message is generated
>> if RX is activated before TX fifo is cleared.
>>
>> Fixes: b389f173aaa1 ("tty/serial: atmel: RS485 half duplex w/DMA: enable
>> RX after TX is done")
>> Signed-off-by: Razvan Stefanescu <razvan.stefanescu@xxxxxxxxxxxxx>
>> Acked-by: Richard Genoud <richard.genoud@xxxxxxxxx>
>> Cc: stable <stable@xxxxxxxxxxxxxxx>
>> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
>> ---
>> drivers/tty/serial/atmel_serial.c | 24 +++++++++++++++++++++---
>> 1 file changed, 21 insertions(+), 3 deletions(-)
>>
>
> Happen to have a version of this for 4.4.y and 4.9.y?
>
> I've queued both of these patches up now, thanks.
>
Thank you for picking them. I've sent the patches for 4.4.y and 4.9.y.
Best regards,
Razvan Stefanescu
