Re: Deauthentications with p54usb

[Larry Finger <Larry.Finger@lwfinger.net>]

Chunkeey@web.de wrote:
> Ahh, wait... screw up: I failed to explain the difference between:
> 
> - powersave (=> responsible for your connection problems)
>    In this mode: the device goes into a lower power state,
>    but continues to listen for dtim beacons and multicast frames,
>    from the AP.
> 
>    mac80211 does not have printks for these ps events,
>    since the device power state may chance every second.
> 
>    howeve, it's possible to trace them through the generic _trace_
>    framework with MAC80211_DRIVER_API_TRACER Kconfig
>    option enabled.
>    
> vs. 
> 
>  - hibernation (soft rfkill that went in with "[PATCH] p54: implement rfkill")
>    In this mode: the device's radio is completely shutdown... so
>    it only makes sense to enter this mode when there's really nothing
>    to do (=> the device is not scanning or associating/associated)
>    
>    mac80211 will printk (with CONFIG_MAC80211_VERBOSE_DEBUG set)
>    whenever the IEEE80211_CONF_IDLE changes. e.g: 
>        phy0: device no longer idle - REASON
>     or:
>        phy0: device now idle
>     in the kernel logs.
> 
>> Turning off CONFIG_CFG80211_DEFAULT_PS stopped the messages,
>> thus it certainly looks like a power saving event.
> so hibernation (rfkill) is fine, just powersave is playing tricks...
> weirdly, intel disabled ps in their driver _again_ not too long ago,
> maybe a coincident, maybe not... do you think you can send me
> a kismet/wireshark/airodump dump whenever the AP kicks the device?

We don't know that hibernation is OK. I just never make my machine
hibernate (suspend to disk) or sleep (suspend to RAM). The last time I
tried it had one or more drivers that would not cooperate, and I have
not tried recently.

I'll try to collect a dump.

> BTW: you can set different PS modes with the old iwconfig utility:
> iwconfig wlanX power off <-- disables PS
> (just like turning off the CONFIG_CFG80211_DEFAULT_PS option)
> 
> iwconfig wlanX power timeout 0 <--- most aggressive PS setting,
> (only uses PS-POLL to retrieve data).
> 
> AFAIK the current default is just "1", maybe your link would be
> totally reliable with a more  _relaxed_ 200, 500 setting...

I'll re-enable CONFIG_CFG80211_DEFAULT_PS and try a more relaxed value
for the power timeout. In any case, with it disabled, there have been
no deauthentications nor disassociations. The link is rock solid.

Larry