Re: [PATCH for-4.19 2/2] tty/serial: atmel: RS485 HD w/DMA: enable RX after TX is stopped

[Greg KH <gregkh@linuxfoundation.org>]

On Wed, Apr 03, 2019 at 03:07:18PM +0000, Razvan.Stefanescu@microchip.com wrote:
> 
> 
> 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@microchip.com>
> >> Acked-by: Richard Genoud <richard.genoud@gmail.com>
> >> Cc: stable <stable@vger.kernel.org>
> >> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> >> ---
> >>   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.

Thanks for those, now queued up.

greg k-h