Message-ID: <1434538909.1884.39.camel@sipsolutions.net> (sfid-20150617_130154_729165_1E60D297)
Subject: Re: [PATCH V3] mac80211: wowlan: suspend: Fix power save state
 stuck in ACTIVE caused by race between suspend and Tx packet.
From: Johannes Berg <johannes@sipsolutions.net>
To: Krishna Chaitanya <chaitanya.mgit@gmail.com>
Cc: linux-wireless <linux-wireless@vger.kernel.org>
Date: Wed, 17 Jun 2015 13:01:49 +0200
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On Wed, 2015-06-17 at 15:52 +0530, Krishna Chaitanya wrote:

> > I still don't like it. I also don't believe that what you're writing is
> > actually true. The only problem I can see is that it leads to higher
> > power consumption *while the system is suspended* - at resume time we
> > send a packet and thus kick the timers...
> "If" we send a packet, but until them the system will still be
> active.

But we *always* send a packet:

ieee80211_reconfig:
...
        /*
         * The sta might be in psm against the ap (e.g. because
         * this was the state before a hw restart), so we
         * explicitly send a null packet in order to make sure
         * it'll sync against the ap (and get out of psm).
         */
        if (!(local->hw.conf.flags & IEEE80211_CONF_PS)) {
                list_for_each_entry(sdata, &local->interfaces, list) {
                        if (sdata->vif.type != NL80211_IFTYPE_STATION)
                                continue;
                        if (!sdata->u.mgd.associated)
                                continue;

                        ieee80211_send_nullfunc(local, sdata, 0);
                }
        }


Then again, you're talking about WoWLAN, but then ...

johannes