Hello Richard,

On Fri, Sep 30, 2016 at 10:58:00AM +0200, Richard Genoud wrote:

Commit 1cf6e8fc8341 ("tty/serial: at91: fix RTS line management when
hardware handshake is enabled") broke the hardware handshake when GPIOs
were used.

Hardware handshake with GPIOs used to work before this commit because
the CRTSCTS flag (termios->c_cflag) was set, but not the
ATMEL_US_USMODE_HWHS flag (controller register) ; so hardware handshake
enabled, but not handled by the controller.

What does the HWHS flag control? What if only RTS is a gpio and CTS is
not? Or the other way round?

What is the problematic setup? I guess it's RTS and CTS are gpios and
with that setting ATMEL_US_USMODE_HWHS is wrong? What happens if that
happens?

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |