Return-path: Received: from mail-px0-f174.google.com ([209.85.212.174]:33391 "EHLO mail-px0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753085Ab0EFWRI convert rfc822-to-8bit (ORCPT ); Thu, 6 May 2010 18:17:08 -0400 MIME-Version: 1.0 In-Reply-To: References: From: "Luis R. Rodriguez" Date: Thu, 6 May 2010 15:16:48 -0700 Message-ID: Subject: Re: 2.6.33.2: Turn tx power off/on for Atheros card To: Yegor Yefremov Cc: linux-wireless@vger.kernel.org, netdev@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Thu, May 6, 2010 at 7:52 AM, Yegor Yefremov wrote: > On Wed, May 5, 2010 at 12:26 PM, Yegor Yefremov > wrote: >> I'm using kernel 2.6.33.2 with AR2413 WLAN card. Issuing >> >> iwconfig wlan0 txpower off >> >> turns txpower off. I can see this status by iwconfig wlan0 and the >> communication with AP terminates. But when I turn the txpower on >> >> iwconfig wlan0 txpower on >> >> nothing happens. Though iwconfig shows the previous tx power value. >> Only ifconfig wlan0 down and then up recovers the transmission. >> >> Is it a known bug or I'm doing something wrong? > > I made some debugging and found out that after iwconfig wlan0 txpower > off dev_close() will be invoked, so that local->open_count will be 0. > The next time txpower on will be called, it will be checked if > local->open_count > 0 and this conditions fails, so no  hardware > configuration will be made. > > I've made a quick and dirty hack, that opens the wireless device by > enabling the txpower, if it was closed before. Is there any proper > solution? Is it really necessary to close device to tunr txpower off? Depends on the type of interfaces you have. For a monitor device it makes no sense to close the device as you should be able to still RX. It also is possible to TX over a monitor device using frame injection so technically setting tx power to off would just mute it and would seem useful. Luis