Re: [RFC 3/3] mac80211: Disable off-channel powersave when software scans are suspended

[Seth Forshee <seth.forshee@canonical.com>]

On Wed, Jan 09, 2013 at 12:03:44PM +0100, Stanislaw Gruszka wrote:
> Hi
> 
> On Tue, Jan 08, 2013 at 12:10:45PM -0600, Seth Forshee wrote:
> > Leaving powersave enabled while the scan is suspended requires the use
> > of PS-Poll to retrieve frames buffered at the AP. PS-Poll isn't a very
> > efficient means of data transfer and may not even work with drivers not
> > supporting powersave. These problems can largely be avoided by simply
> > disabling off-channel powersave when the scan is suspended and enabling
> > it again when returning to off-channel operation.
> > 
> > The results of this change are fantastic. Previously when using iperf I
> > would see greatly decreased throughput (often dropping to 0 bits/sec for
> > several seconds) and very high packet loss during software scans. This
> > patch completely eliminates the packet loss and reduces the loss in
> > throughput to very reasonable levels.
> 
> I posted a patch, which remove offchannel_ps_disable argument from
> ieee80211_offchannel_return, since there were possible AP and STA power
> save state mismash:
> 
> http://marc.info/?l=linux-wireless&m=135601089321822&w=2
> 
> It should give the same effect on performance as this patch.

I guess I missed that one in my pile of post-holiday emails. I agree, it
ought to have the same effect as this patch.

Seth