On Mon, Jul 29, 2019 at 11:56:48PM -0700, Life is hard, and then you die wrote:
> On Mon, Jul 29, 2019 at 03:22:03PM +0200, Dmitry Torokhov wrote:
> > On Sun, Jul 21, 2019 at 12:05:23AM -0700, Ronald Tschalär wrote:
> > Question: is it possible to read command response synchronously as well?
> > I.e. I was wondering if we could add 2 (or 1?) more read xfers for the
> > actual result that is coming after the status response, and then we
> > could use spi_sync() to send the command and read the whole thing.
>
> Yes'ish. But you still need to wait for the GPE to know when to read
> the response, and while you're doing so any number of keyboard and
> trackpad events may arrive (i.e. you may need to do any number of read
> xfers). I suppose those events could all just be discarded, though. So
> something like this:
>
> assemble-info-cmd(write_msg)
> spi_sync(write_msg)
>
> while (1) {
> wait_event_timeout(wait_queue, gpe_received, timeout)
> spi_sync(read_msg)
> if (is-info-cmd-response(read_msg))
> break
> }
Just a side note if you ever going to implement such loops.
Consider in this or similar case do {} while approach with more straight exit
conditional.
Like
assemble-info-cmd(write_msg)
do {
spi_sync(read_msg)
wait_event_timeout(wait_queue, gpe_received, timeout)
} while (!is-info-cmd-response(read_msg)
> and also modify the gpe-handler to wake the wait_queue instead of
> issuing an spy_async() while doing the above.
>
> I guess the advantage would certainly be the need to avoid the
> spi-flushing in case of a timeout, at the expense of some slight
> duplication of some of the received-message handling logic (would
> refactor make most re-usable, of course).
>
> So would this be the preferred approach then?
--
With Best Regards,
Andy Shevchenko
