[ath9k-devel] ath9k in wireless-testing won't work in AP mode

[Pavel Roskin <proski@gnu.org>]

On Sat, 2010-01-30 at 21:46 +0100, Felix Fietkau wrote:

> > But using the value of 10 instead of 9 for sc->beacon.slottime does the
> > trick.  That's the minimal patch that works for me.
> > 
> > Perhaps we should be using ATH9K_SLOT_TIME_9 there (see mac.h) and
> > define it to 10.
> That value would still be wrong, though. According to the 802.11 docs,
> the slot time for 2.4 GHz has to be set to 9 usec, not 10.

OK, we may need a fudge factor elsewhere.  Ideally, it should be based
on Atheros documentation, but we cannot just keep the driver in a
non-functioning state if we don't have such documentation.

> If this is a bug in the hardware, we need to know about the implications
> before we pick a value that just happened to work in our tests, but may
> not work in all cases.
> slottime=9, acktimeout=64 is what the initvals use, so that's tested by
> Atheros. If we continue to receive no comments from Atheros on this
> issue, we should probably use those values by default.
> By the way, 5 GHz seems to be unaffected by this issue, which makes this
> a little suspicious.

Indeed, it's unaffected.  But the reason is because sifstime is 16 for
the band, not 10, which pushes acktimeout to 25.  I tried setting
acktimeout to a lower value.  23 is OK on channel 165, 22 is not.  22 is
OK on channel 36 though.

-- 
Regards,
Pavel Roskin