Message-ID: <1360360665.29851.37.camel@jlt4.sipsolutions.net> (sfid-20130208_225808_512761_8AD772AE)
Subject: Re: [RFCv2 2/3] mac80211: mesh power save doze scheduling
From: Johannes Berg <johannes@sipsolutions.net>
To: Marco Porsch <marco@cozybit.com>
Cc: mcgrof@qca.qualcomm.com, jouni@qca.qualcomm.com,
	vthiagar@qca.qualcomm.com, senthilb@qca.qualcomm.com,
	linux-wireless@vger.kernel.org, devel@lists.open80211s.org,
	ath9k-devel@lists.ath9k.org
Date: Fri, 08 Feb 2013 22:57:45 +0100
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On Fri, 2013-02-08 at 11:09 +0100, Marco Porsch wrote:

> >> For mesh Awake Windows wakeup on SWBA (beacon_get_tim) and start
> >> a timer which triggers a doze call on expiry.
> >
> > That seems questionable -- drivers are not required to request each
> > beacon. I know you only want to make it work on ath9k, but I don't think
> > "stretching" the API, without even documenting it, is a good idea.
> 
> Currently, we already use ieee80211_beacon_get_tim as time reference for 
> mesh sync's adjust_tbtt. And, as far as I know, all mesh-capable drivers 
> use the call for each and every beacon.

Oops, why did I miss that before? :-)

> So what would you recommend: keep using beacon_get and adding 
> documentation - or - creating an exported callback for awake_window_start?

I guess you could add it... However, I don't really fully understand.
There's no guarantee that fetching the beacon is done anywhere close to
TBTT? Or does ath9k happen to do it just after TXing a beacon? You're
encoding quite a lot of ath9k-specific assumptions here it seems?

johannes