Re: [PATCH] spi: pl022: Fix broken spidev when DMA is enabled

Geert Uytterhoeven
2014-10-09T13:59:21Z

On Wed, Oct 8, 2014 at 8:21 PM, Mark Brown <broonie@kernel.org> wrote:
> On Wed, Oct 08, 2014 at 09:14:35AM -0700, Ray Jui wrote:
>> Thanks for the reply. It looks like you are also the maintainer of spidev.
>> In this case, could you please help to confirm that you expect spidev to use
>> separate buffers for TX and RX? If so, I can go ahead and make the change in
>> spidev.
>
> Yes, that would be my expectation for maximum robustness (or if it is
> going to use one buffer it explicitly maps it for mixed use but I'd
> expect that to be asking for trouble).

Having two separate buffers avoids false successes when running
"spidev_test --loop" on a buggy SPI master driver.
Been there, done that ;-)

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds