Big delays between an AR5416 AP and its clients
Adrian Chadd
adrian.chadd at gmail.com
Sat Dec 3 16:22:52 UTC 2011
2011/12/4 Gustau Pérez <gperez at entel.upc.edu>:
> I see nothing particular in my dmesg with wlandebug enabled. I see the
> AR5416 complaining about a beacon off-channel for a MAC I don't know about.
> I also see the iphone's MAC going power save with a message like this:
>
> power save mode on, 2 sta's in ps mode
Well, it _is_ doing power saving, which I expected. This doesn't at
all correlate with the periodicity of the issue?
> I also see all of those messages with a pre r227364 kernel, so I would say
> they are harmless and not related to the issue.
*nod* I'm just looking if they correlate timewise with the growing latency..
> However, I see these the following entries in my dmesg when using r227364:
>
> Dec 3 16:46:27 harkserver kernel: Timeout while waiting for nf
> to load: AR_PHY_AGC_CONTROL=0x41d1a
> Dec 3 16:46:27 harkserver kernel: Timeout while waiting for nf
> to load: AR_PHY_AGC_CONTROL=0x41d1a
>
> Dec 3 16:18:27 harkserver kernel: ar5416PerCalibrationN: NF
>
> calibration didn't finish; delaying CCA
> Dec 3 16:18:27 harkserver kernel: ar5416PerCalibrationN: NF
>
> calibration didn't finish; delaying CCA
>
> I don't see those messages with a previous revision because they appear to
> be part of r227364. Those problems appear from time to time, could they and
> the latency increase be related?
That could be related. If the device thinks the air is constantly busy
(or it's spending a lot of time trying to TX) then it may fail NF
calibration.
I just wonder what I've changed which may be causing the NIC to behave this way.
What's interesting (!) is that I have seen similar reports with ath9k
in Linux. I wonder if part of the 11n work (that ath9k has also
borrowed) has the same broken behaviour on the AR5416.
Can you please file all of this in the PR? I'll have finished moving
by December 15 so I can start trying to replicate this issue and help
you debug it.
Thanks,
Adrian
More information about the freebsd-wireless
mailing list