Am Freitag 04 Juni 2010 schrieb Johannes Berg:
> On Fri, 2010-06-04 at 12:22 +0200, Helmut Schaa wrote:
>
> > This meant that minstrel most of the time selected MCS15 as tx rate which
> > resulted in a huge number of retries and thus a very slow throughput.
> >
> > status.c:
> >
> > 178 /* the HW cannot have attempted that rate */
> > 179 if (i >= hw->max_rates) {
> > 180 info->status.rates[i].idx = -1;
> > 181 info->status.rates[i].count = 0;
> >
> > Johannes, is there a valid reason for this check in status.c. Can we remove
> > it without breaking anything else?
>
> IIRC there were/are some drivers that were not terminating the rates[]
> array correctly with a -1, thus this code.
Understood, so it's a driver workaround ;)
Maybe we should check which driver doesn't set it and fix these?
> > What other options would we have to fix this issue? Just use max_rates = 4
> > in rt2800 even if we will only use the first rate provided by minstrel and
> > then fall back to the global fallback setup (I tried that already and it
> > works just fine but seems not correct to me)?
>
> p54 kinda does some trickery in this area too, not really sure what to
> do though.
Thanks for the pointer, p54 just sets max_rates=4 even if it cannot support
it.
So, if you would like to keep the check I'll just use max_rates=4 in rt2800.
Helmut
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