Re: [PATCH v2 0/3] mac80211 suspend/resume

[Johannes Berg <johannes@sipsolutions.net>]

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On Tue, 2009-01-06 at 12:07 -0500, Bob Copeland wrote:
> On Tue, 06 Jan 2009 11:45:06 -0500, Dan Williams wrote
> > You still want to tell NM to go to sleep so it doesn't see the
> > disconnection from the supplicant (triggered by the driver because it
> > was going to sleep), and thus try to reconnect, or try a different AP.
> 
> Well, I tried it without the hack and it works (connection stays up 
> over a short suspend period).  This is with the new mac80211 suspend
> patches, where suspend/resume looks like this:
> 
> suspend:
>   suspend userspace (freezes NM)
>   save bssid, keys etc
>   if wlan0 up
>      ifdown wlan0 (note NM is already frozen)
>   power down hw
> 
> resume:
>   power up hw
>   if wlan0 was up
>      ifup wlan0
>   reload config, bssid, ...
>   resume userspace
> 
> However, _with_ the current procedure of telling NM to go to sleep, it
> tries to reconnect after resume because NM takes care of downing the
> interfaces.  As a result mac80211 never gets the chance to save the
> state of the running interfaces.

You mean restore?

Does that mean there's a race condition now, between userspace config
and the resume stuff? Can't we fix that by taking the rtnl?

johannes

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