Hi Richard,
Richard Genoud <richard.genoud@xxxxxxxxx> writes:
> Hi Sergey,
>
> In the commit 9bcffe7575b7 ("tty/serial: at91: fix hardware handshake
> on Atmel platforms"),
> it's said that the RTS/CTS handshake *driven by the controller* is
> broken on sama5d3 platforms.
>
> But, it works perfectly fine if it is driven by Linux.
Yes, I thought I made it clear I only consider hardware handshake case.
As a side-note, in my experience software handshake rarely works
perfectly in practice, due to its inherent limitations. It works
expected, yes, but "perfectly fine" sounds too optimistic to me.
> That said, I've effectively seen the RTS breakage on sama5d3. (it's
> not random, it's 100% reproductible).
That contradicts my experience though. I believe I just effectively
commented-out the
if (atmel_use_dma_rx(port) &&
!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_CTS)) {
part of the code to always use exactly hardware handshake, and it does
work.
Looks like I need to further research the issue then and make sure I do see
what I think I see.
> I did not try to run atmel's bare metal code, but IMHO, the
> usart_hw_handshaking example should fail.
I didn't either, but I did run Linux driver with hardware handshake
re-enabled as I've said above, and it seems to be working on my
sama5d3-based board.
-- Sergey
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