Message-ID: <1360767970.8868.24.camel@jlt4.sipsolutions.net> (sfid-20130213_160625_377832_EF71C4D5)
Subject: Re: [PATCH 1/4] mac80211: Convert PS configuration from a binary
 flag to a set of modes
From: Johannes Berg <johannes@sipsolutions.net>
To: Seth Forshee <seth.forshee@canonical.com>
Cc: linux-wireless@vger.kernel.org,
	Arend van Spriel <arend@broadcom.com>,
	"John W. Linville" <linville@tuxdriver.com>,
	"Luis R. Rodriguez" <mcgrof@qca.qualcomm.com>,
	Jouni Malinen <jouni@qca.qualcomm.com>,
	Vasanthakumar Thiagarajan <vthiagar@qca.qualcomm.com>,
	Senthil Balasubramanian <senthilb@qca.qualcomm.com>,
	Christian Lamparter <chunkeey@googlemail.com>,
	Ivo van Doorn <IvDoorn@gmail.com>,
	Gertjan van Wingerde <gwingerde@gmail.com>,
	Helmut Schaa <helmut.schaa@googlemail.com>,
	Larry Finger <Larry.Finger@lwfinger.net>,
	Chaoming Li <chaoming_li@realsil.com.cn>,
	Wey-Yi Guy <wey-yi.w.guy@intel.com>,
	Intel Linux Wireless <ilw@linux.intel.com>,
	Luciano Coelho <coelho@ti.com>, ath9k-devel@lists.ath9k.org,
	brcm80211-dev-list@broadcom.com, users@rt2x00.serialmonkey.com
Date: Wed, 13 Feb 2013 16:06:10 +0100
In-Reply-To: <1360184478-31481-2-git-send-email-seth.forshee@canonical.com>
References: <1360184478-31481-1-git-send-email-seth.forshee@canonical.com>
	 <1360184478-31481-2-git-send-email-seth.forshee@canonical.com>
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Sender: linux-wireless-owner@vger.kernel.org

On Wed, 2013-02-06 at 15:01 -0600, Seth Forshee wrote:
> The powersave configuration in struct ieee80211_conf is currently a
> binary state, either enabled or disabled. This is inadequate for
> expressing the situation during off-channel operation, when powersave is
> set at the AP to request bufferring of frames but the hardware remains
> fully awake. Some drivers (e.g. brcmsmac) need to perform configuration
> to support this in-between state but lack the information to do so.
> 
> To prepare for adding an off-channel powersave mode, expand the current
> powersave configuration flag to two bits to support expressing another
> state. Add helper functions for setting and retrieving the state, and
> convert mac80211 and drivers to use these functions.
> 
> In changing from a binary flag to powersave mode, also update the
> terminology used to name the states for clarity. The "enabled" state is
> changed to "doze" to indicate a low power hardware state, and the
> "disabled" state is changed to "awake" to indicate a fully powerd on
> hardware state. This is consistent with the terminology defined in IEEE
> 802.11-2012 section 10.2.1.2.

Ok so I'm reviewing this again.

I'm not really convinced this is the right thing to do. Sooner or later,
multi-virtual interface support will become more relevant, and then all
of this is completely moot because then powersave is entirely disabled
and not handled right now.

Is all this really worth it? It seems a quick fix for brcmsmac might be
to always set the powersave bit when IEEE80211_CONF_OFFCHANNEL is
enabled in the config, and then go implement a real solution like I
described earlier with powersave being separated out of the core
mac80211 routines, and actually made possible for multiple interfaces?

johannes