Re: [ath5k-devel] [PATCH 1/1] ath5k: fix hw rate index condition

Pavel Roskin
2009-03-01T05:22:13Z

On Thu, 2009-02-26 at 22:06 -0500, Bob Copeland wrote:
> On Thu, Feb 26, 2009 at 06:39:12PM -0800, Luis R. Rodriguez wrote:
> > Might be worth adding a note why this is the case. Can't we simply avoid
> > this by checking earlier for the error or simply assigning it an actual
> > default _good_ hw rate value?
>
> I guess an alternative is to initialize to 0, that would count any rx
> packets whose hw rate we don't know about as the base rate, so it would
> probably bias the RC to 1mb, but this is already one of those 'should
> never happen' cases.

I would prefer that we don't hide problems.

If we don't know why we cannot get a valid rate, we should use WARN_ON
and find out why and when it happens. I'm fine with using a bogus rate
with WARN_ON.

If we decide that we indeed cannot find the actual rate, then WARN_ON
should be removed and the bogus rate replaced with an "unknown rate",
that is, a special value that is never translated to a valid rate and
never given to any rate control algorithm. Using a bogus rate without a
warning is wrong in my opinion.

It should be possible to represent "unknown rate" as such. That applies
to all drivers. I remember that b43 also failed to report the rate in
some cases (for the first received packet or something like that).

--
Regards,
Pavel Roskin