On Wed, Mar 28, 2012 at 03:47:21PM +0200, Timo Lindhorst wrote:
> > > > + if (!ack)
> > > > + for (i = 0; i < IEEE80211_TX_MAX_RATES; i++)
> > > > + tx_count[i] = txi->control.rates[i].count;
> > > > +
> > > >
> > > > ieee80211_tx_info_clear_status(txi);
> > > > if (!(txi->flags & IEEE80211_TX_CTL_NO_ACK) && ack)
> > > >
> > > > txi->flags |= IEEE80211_TX_STAT_ACK;
> > > >
> > > > +
> > > > + if (ack) {
> > > > + txi->status.rates[0].count = 1;
> > > > + txi->status.rates[1].idx = -1;
> > > > + } else {
> > > > + for (i = 0; i < IEEE80211_TX_MAX_RATES; i++)
> > > > + txi->control.rates[i].count = tx_count[i];
> > > > + }
> > > > +
> > > >
> > > > ieee80211_tx_status_irqsafe(hw, skb);
> > > >
> > > > }
> > >
> > > I know: backing up the count values, clearing the status, and restoring
> > > the values if necessary is kind of ugly. Would it be better to partly
> > > clear the status manually instead of using
> > > ieee80211_tx_info_clear_status() ?
> >
> > Yeah just noticed the ieee80211_tx_info_clear_status() in there too...
> >
> > OTOH, what are you using this for?
> While working on some modifications to the rate control code, I thought it
> would be handy to use mac80211_hwsim for debugging and testing. Thereby I
> noticed that the tx status does not report any tx attempts, thus the rate
> control could not work at all.
>
> > It seems almost like we should always
> > just set
> > txi->status.rates[0].count = 1;
>
> At least,
> txi->status.rates[1].idx = -1;
> has to be set too, to indicate that only the first rate was used.
>
>
> > since we never attempted multiple transmits? I'm not really sure though,
> > it's a corner case ...
> We would only attempt multiple transmits if the receiver is not responding to
> unicast frames -- maybe because it has failed or switched the channel.
> Probably not a common use case, but that was what I was testing...
>
>
> > I could also imagine this being populated by
> > userspace (wmediumd) but I guess that isn't there now ...
> Right, but if you are not using wmediumd but the bare mac80211_hwsim ideal
> channel, there would be no rate information and thus no rate adaption through
> the rate control algorithm.
>
> Regards
> Timo
Johannes, does this satisfy your concerns?
John
--
John W. Linville Someday the world will need a hero, and you
linville@xxxxxxxxxxxxx might be all we have. Be ready.
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