Re: [PATCH v6 2/2] mac80211: support DTPC IE (from Cisco Client eXtensions)

[Johannes Berg <johannes@sipsolutions.net>]

On Wed, 2014-09-03 at 06:48 -0700, Steinar H. Gunderson wrote:
> Linux already supports 802.11h, where the access point can tell the
> client to reduce its transmission power. However, 802.11h is only
> defined for 5 GHz, where the need for this is much smaller than on
> 2.4 GHz.
> 
> Cisco has their own solution, called DTPC (Dynamic Transmit Power
> Control). Cisco APs on a controller sometimes but not always send
> 802.11h; they always send DTPC, even on 2.4 GHz. This patch adds support
> for parsing and honoring the DTPC IE in addition to the 802.11h
> element (they do not always contain the same limits, so both must
> be honored); the format is not documented, but very simple.
> 
> Tested (on top of wireless.git and on 3.16.1) against a Cisco Aironet
> 1142 joined to a Cisco 2504 WLC, by setting various transmit power
> levels for the given access points and observing the results.
> The Wireshark 802.11 dissector agrees with the interpretation of the
> element, except for negative numbers, which seem to never happen
> anyway.

Applied both.

johannes