Hi Mark,
On Fri, Jan 31, 2014 at 1:26 PM, Mark Brown <[email protected]> wrote:
> On Fri, Jan 31, 2014 at 01:00:31PM +0100, Geert Uytterhoeven wrote:
>> One other thing: I haven't tried your patch yet, but I'm afraid the 10 ms
>> may be too small.
>
>> E.g. with PIO-based RSPI I don't get more than 2 Mbps, even though
>> spi-max-frequency = <30000000>, due to the PIO and interrupt overhead.
>> Hence a 1 MiB read would take ca. 4s, while your timeout would be 300 ms.
>
> Hrm, I wouldn't have expected something doing PIO in more than one burst
> to be letting the transfer run in the background. Though I suppose that
> might make sense in some situations...
While I've been thinking about moving more code to the interrupt handler,
the current RSPI transfer_one() is indeed still synchronous, so the timeout
doesn't apply yet.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]
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
--
To unsubscribe from this list: send the line "unsubscribe linux-spi" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
