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From: Helmut Schaa <helmut.schaa@googlemail.com>
To: "linux-wireless" <linux-wireless@vger.kernel.org>
Subject: mac80211 sw scan: passive dwell time
Date: Tue, 30 Jun 2009 13:09:30 +0200
Cc: Johannes Berg <johannes@sipsolutions.net>
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Hi,

in mac80211's software scan implementation the passive dwell time
IEEE80211_PASSIVE_CHANNEL_TIME is set to (HZ / 5) which means we
stay 200ms on each passive channel. Compared to iwlwifi's hw scan
and the old ipw* drivers which use values around 120ms this is quite
long.

Reducing the passive dwell time from 200ms to 120ms could save us
something around a second on cards capable of 11a and we would be still
able to catch beacons from most access points (assuming a ~100ms beacon
interval).

Objections?

Thanks,
Helmut