ural driver stalls under FreeBSD7.1

[Weongyo Jeong]

On Thu, Feb 26, 2009 at 06:04:17PM -0800, Sam Leffler wrote:
> Bengt Ahlgren wrote:
> >Weongyo Jeong <weongyo.jeong at gmail.com> writes:
> >  
> >>On Thu, Feb 26, 2009 at 01:20:36PM +0900, Nathan Butcher wrote:
> >>    
> >>>I have a Buffalo WLI-U2-KG54-AI wireless USB adaptor.
> >>>It has been malfunctioning for quite a while under FreeBSD7.0 and 7.1
> >>>
> >>>Typically, It works for a while until eventually it stalls data
> >>>transfers completely. It always seems to do this after an unspecified
> >>>amount of time.
> >>>
> >>>I know the hardware isn't at fault because the device works fine under
> >>>Linux.
> >>>      
> >>Could you please check that `ifconfig <ifname> -bgscan' disabling the
> >>background scan helps your symptom?
> >
> >The above sounds like the same problem as this:
> >
> >http://lists.freebsd.org/pipermail/freebsd-mobile/2009-February/011376.html
> >http://lists.freebsd.org/pipermail/freebsd-mobile/2009-February/011343.html
> >
> >The problem is in the background scanning logic in sys/net80211.
> 
> I don't see how you come to this conclusion.  ural is a totally 
> different driver than ath and so far as I can recall you never found the 
> cause for your problem w/ ath.  Most of the usb wireless drivers do a 
> haphazard job of synchronizing async tasks like bg scan with the 
> foreground tx/rx processing.  This can lead to firmware and/or usb 
> issues.  ath does not have these issues but I am aware of at least one 
> problem w/ bg scanning in ath under RELENG_7 (that is not present in HEAD).

I agree with sam because I saw some cases like stalls during background
scanning that most of them I think it's caused by H/W miss-operation or
miss-configuration by mistakes of driver.

regards,
Weongyo Jeong