Re: [ath9k-devel] ath9k: ap tsf seems random and only uses lower 24 bits or so

[Benoit Papillault <benoit.papillault@free.fr>]

Le 29/06/2010 00:55, Felix Fietkau a écrit :
> On 2010-06-29 12:31 AM, Björn Smedman wrote:
>> Hi all,
>>
>> I'm getting weird values from the debugfs file ieee80211/phy0/tsf: the
>> value goes up and down rather randomly and only the lower 24 bits or
>> so seem to ever be used (see below for details).
>>
>> The only thing running on phy0 is a single ap interface (and the
>> monitor companion that hostapd sets up). I was expecting tsf to
>> increase monotonically until all 64 bits had been used.
>>
>> For a moment I thought it might be the kernel snprintf (on mips)
>> playing a trick on me so I tried the following patch. But the result
>> is the same.
> IMHO the most likely problem source is stuck beacons. Please compile the
> driver with the debug option enabled and load it with
> insmod ath9k debug=0x00000100
>
> - Felix

Humm... I observed a similar behavior a while ago because only the 15 
lower bits of rstamp were used when being extended (but rstamp is 32 
bits in fact). If so, it has been fixed by Felix in the following commit :

commit a6d2055b02dde1067075795274672720baadd3ca
Author: Felix Fietkau <nbd@openwrt.org>
Date:   Sat Jun 12 00:33:54 2010 -0400

     ath9k: fix extending the rx timestamp with the hardware TSF

Regards,
Benoit