On Wed, Nov 24, 2010 at 10:55 PM, Nick Kossifidis <mickflemm@xxxxxxxxx> wrote:
> 2010/11/24 Jonathan Guerin <jonathan@xxxxxxxxxxxx>:
>>
>>> diff --git a/drivers/net/wireless/ath/ath5k/pcu.c b/drivers/net/wireless/ath/ath5k/pcu.c
>>> index e691378..4556f29 100644
>>> --- a/drivers/net/wireless/ath/ath5k/pcu.c
>>> +++ b/drivers/net/wireless/ath/ath5k/pcu.c
>>> @@ -763,7 +763,7 @@ ath5k_hw_check_beacon_timers(struct ath5k_hw *ah, int intval)
>>> * @ah: The &struct ath5k_hw
>>> * @coverage_class: IEEE 802.11 coverage class number
>>> *
>>> - * Sets slot time, ACK timeout and CTS timeout for given coverage class.
>>> + * Sets IFS intervals and ACK/CTS timeouts for given coverage class.
>>> */
>>> void ath5k_hw_set_coverage_class(struct ath5k_hw *ah, u8 coverage_class)
>>> {
>>> @@ -772,7 +772,7 @@ void ath5k_hw_set_coverage_class(struct ath5k_hw *ah, u8 coverage_class)
>>> int ack_timeout = ath5k_hw_get_default_sifs(ah) + slot_time;
>>
>> This is not quite right:
>>
>> According to the 802.11-2007 spec document, the ACKTimeout value is
>> (Section 9.2.8 ACK procedure):
>> ACKTimeout = aSIFSTime + aSlotTime + aPHY-RX-START-Delay
>>
>> From Table 17-15—OFDM PHY characteristics, the values are:
>> aSIFSTime = 16
>> aSlotTime = 9
>> aPHY-RX-START-Delay = 25
>>
>> Therefore, ACKTimeout = 50
>>
>> Ignoring my uniformed comments from before, this is the only thing I
>> can see that's wrong.
>>
>> Cheers,
>>
>> Jonathan
>
> Hmm I didn't mess with set_coverage_class so i didn't look up for ack
> timeout. That phy-rx-start-delay is standard value or hw specific ?
> Also does it change with clockrate (bwmodes) ? We already have a phy
> activation -> rx start delay (check patch 25). It's 10.000 on RF5111
> and 2.000 on RF5112 and later, if we divide by A clock it's 250 on
> RF5111 and 50 on RF5112 and later. Do you think it's related ?
The phy-rx-start-delay is set in the standard. I'll find you the
relevant pages soon.
I'll look up the others tomorrow. I'm feeling pretty sick today, so
not sure if I'll get a chance.
Cheers,
Jonathan
>
> --
> GPG ID: 0xD21DB2DB
> As you read this post global entropy rises. Have Fun ;-)
> Nick
>
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