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 13:45, Felix Fietkau a écrit :
> On 2010-06-29 8:08 AM, Benoit Papillault wrote:
>> 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 :
> Nope, different issue. The TSF extending applies only to rx timestamps,
> however Björn has been observing weird TSF values from the hw register.
> The Rx TSF timestamp is pretty much irrelevant in AP mode.
>
> - Felix
>

Ah, right and.. right! :-)
Sorry for the noise.

Regards,
Benoit