On Wed, Aug 20, 2014 at 5:55 PM, Adrian Chadd <adr...@freebsd.org> wrote:
> On 20 August 2014 16:33, PseudoCylon <moonlightak...@yahoo.ca> wrote:
>> On Wed, Aug 20, 2014 at 1:29 PM, Adrian Chadd <adr...@freebsd.org> wrote:
>>> Are you seeing RX CRC errors for all rates? CCK? OFDM? HT? At all distances?
>> CCK not sure, OFDM and HT yes. And at wide range of distances. (Tx
>> rates usually hit mcs 12 to 14 with 2s ht20 ap)
>>> There's a handful of things we can look at to see what's causing it
>>> once some more digging is done.
>>> (Eg, HT? could be guard interval. OFDM has similar issues, there's
>>> typically ways to configure how much time between each symbol is left
>>> before transmitting the next one. It may not be doing CTS-to-self, or
>>> it may not be advertising the right thing via NAV, or it may be
>>> ignoring CCK, or the receive gain tables are all messed up, etc.)
>> I have looked into stuff I was able to dig out from other src codes,
>> ie protection, ifs, nav, bk slot. (Because I do not have datasheet,
>> every thing is based on my guesses.) One thing I could not figure out
>> is if on-chip memory is properly allocated for rx pkt. (It seems
>> memory can be allocated for different things, ie beacon, enc keys).
> So CRC errors are pretty normal with wifi. Even a tiny bit of
> interference generates CRC errors. That's why there's an ACK and retry
> mechanism. :P
> If you're hitting MCS 12 then you're doing pretty well. A-MPDU will
> see lots of CRC errors just because of how long the transmissions are
> and how easily corrupted things can get. That's again why there's a
> quick retry mechanism for things.

To clarify, tx on run hits mcs 12 to 14. I assume tx on run is
working. But, tx on ap can hit 39mbps at the best, most likely due to
high rx crc error rates on run.

> What %age errors are you seeing?

Constantly 70 to 80 rx crc errors/sec during active downloads. (h/w
does not count total rx, so cannot tell the %.)

> -a
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