Re: lost connectivity until "wpa_cli reassociate" is issued

2016-01-07 Thread David Mosberger 
Ben,

On Thu, Jan 7, 2016 at 9:24 AM, Ben Greear <gree...@candelatech.com> wrote:
> On 01/07/2016 08:19 AM, David Mosberger wrote:
>>
>> We are seeing a curious issue where WLAN connectivity sometimes
>> gets stuck until a "wpa_cli reassociate" command is issued.
>>
>> At the WPA level, everything appears to be working fine)
>> (see thread starting at
>> http://lists.infradead.org/pipermail/hostap/2016-January/034454.html).
>
> I don't remember seeing you mention the driver and NIC you are using.
>
> I think this is likely a driver bug, so please provide that info.

Sure, we're using rtl8192cu.  I started out suspecting a driver bug as
well, but since we're processing management frames during those
"stuck" periods just fine (see
debug output in
http://lists.infradead.org/pipermail/hostap/2016-January/034459.html),
I'm not so sure anymore.  Like mac80211, we have patched rtl8192cu
driver with current
bug-fixes already.

  --david
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Re: lost connectivity until "wpa_cli reassociate" is issued

2016-01-07 Thread David Mosberger 
On Thu, Jan 7, 2016 at 9:32 AM, Krishna Chaitanya
 wrote:

> Management frames use a different queue (VO)
> from the logs it looks like a data path issue in driver/FW.
>
> The re-association might be clearing/triggering TX in driver
> solving the issue.

That sounds plausible to me.  Is there an easy way to see the queues?
I haven't tried debugfs yet.

  --david
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Re: lost connectivity until "wpa_cli reassociate" is issued

2016-01-07 Thread David Mosberger 
Ben,

On Thu, Jan 7, 2016 at 9:33 AM, Ben Greear  wrote:

> Could be
> a power-save issue perhaps.

That was our thought, too.  Particularly, since if there is steady
traffic (at least a ping every 8 seconds), the problem does not appear
to occur.

However, the rtl8192cu doesn't support power-saving mode and in any
case, we made sure it's off:

  # iw wlan0 get power_save
  Power save: off

> I assume you have sniffed to see if any frames are going out on the air 
> during the time of trouble?

No, I'm not actually sure how I'd do that.  The site we see this most
frequently with is
remote and we don't have any special WiFi packet sniffer.

> If correct packets go out on the air and AP doesn't answer, then likely AP
> problem.

Not likely an AP problem, since we're seeing this with multiple APs of
different brands etc.

> If pkts don't get on the air, then check to see if they at least get to
> the driver.

Yeah, that should be easy to do, I suppose.  We had rtl8192cu
debugging turned on
before but at that time it didn't help.

> If they don't get to the driver, then probably it is a kernel/stack issue.
>
> If they get to the driver but not on the air, then NIC and/or it's firmware
> and/or the driver is likely the culprit.

Thanks for your thoughts!

  --david
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Re: lost connectivity until "wpa_cli reassociate" is issued

2016-01-07 Thread David Mosberger 
On Thu, Jan 7, 2016 at 9:58 AM, Krishna Chaitanya
 wrote:

> We can check pending packets per queue at mac80211, but first
> we need some info from driver level. Someone familiar with RTL
> should help.
>
> cat /sys/kernel/debug/ieee80211/phy*/queues
>
> If you see non-zero packets here (or) if the queue is stopped
> that might explain this behavior...

Cool.  I'll check that next time it happens, thanks!

  --david
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