On Jan 21, 2008 11:05 AM, Ivo van Doorn <ivdoorn@xxxxxxxxx> wrote:
> Hi,
>
> > > Then there is a problem for rt2x00. Since the mactime isn't known.
> > > rt2400pci is the _only_ device which has a RX_END_TIME field in the
> > > RX descriptor.
> >
> > one workaround could be to simply use the current TSF at the time in the
> > tasklet or interrupt handler (to be more close to the actual rx time). this
> > should be sufficient to catch most cases where an IBSS merge is necessary -
> > usually the beacon's TSF will be much higher than the local TSF.
>
> Should the driver to this, or should mac80211 handle that?
The driver should if it has access to some the mactime of the received
packet otherwise yes -- I think mac80211 can handle this using the
supplied get_tsf().
> Personally I think it is something for the mac80211 layer since the driver will
> give what it can, and can be sure that it is what mac80211 expects instead of
> drivers interpreting what mac80211 might want as replacement.
> If mac80211 needs the TSF value when no mac time is given, it could just
> use the get_tsf() callback function to the driver to get the substitute. When the
> get_tsf() callback is not provided, then mac80211 can complain about missing
> information.
Agreed, how about something like this modified to Bruno's patch:
+ if (rx_status->flag & RX_FLAG_TSFT)
+ mactime = rx_status->mactime;
+ else {
+ if (!local->ops->get_tsf) {
+ WARN_ON(1);
+ mactime = -1LLU;
+ if (net_ratelimit())
+ printk(KERN_WARNING "%s: cannot determine if "
+ "IBSS merge is required", dev->name);
+ }
+ else {
+ if (net_ratelimit())
+ printk("Could not get detailed timestamp
of beacon "
+ during reception, using the
driver's TSF timer for mactime\n")
+ mactime = local->ops->get_tsf(local_to_hw(local));
+ }
+ }
We could just not support IBSS for driver's without a get_tsf(). Thoughts?
Luis
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