Return-path: Received: from lo.gmane.org ([80.91.229.12]:54973 "EHLO lo.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752622Ab1LSMeH (ORCPT ); Mon, 19 Dec 2011 07:34:07 -0500 Received: from list by lo.gmane.org with local (Exim 4.69) (envelope-from ) id 1RccPq-0008Qt-CK for linux-wireless@vger.kernel.org; Mon, 19 Dec 2011 13:34:02 +0100 Received: from 207.59.80.172 ([207.59.80.172]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Mon, 19 Dec 2011 13:34:02 +0100 Received: from viscous.liquid by 207.59.80.172 with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Mon, 19 Dec 2011 13:34:02 +0100 To: linux-wireless@vger.kernel.org From: Daniel Smith Subject: Re: Question about IEEE80211_TX_CTL_NO_ACK in ath_9k Date: Mon, 19 Dec 2011 07:33:45 -0500 Message-ID: (sfid-20111219_133411_312636_1BF4C827) References: <4EED232D.3010208@lwfinger.net> <20111219112845.C748820066@mail.watchdata.com.cn> Mime-Version: 1.0 Content-Type: text/plain; charset=GB2312 In-Reply-To: <20111219112845.C748820066@mail.watchdata.com.cn> Sender: linux-wireless-owner@vger.kernel.org List-ID: Hi! On 12/19/2011 6:38 AM, ???? wrote: > Hi everybody! > > My wireless card is AR9280. I set the IEEE80211_TX_CTL_NO_ACK flag before > send a packet, but found it no use. It still wait for an ACK. Then I read > the code, > in ath9k_htc_tx_data(htc_drv_txrx.c) , it seems there is only two flags: > > #define ATH9K_HTC_TX_CTSONLY 0x1 > #define ATH9K_HTC_TX_RTSCTS 0x2 > > None is about ack. > > Does anyone know how to make this flag work properly? > As an FYI if your card is a AR9280, then you should be looking in xmit.c and not at the HTC related code. I am also working on this issue to enable per-frame no-ack and have already tracked it down to the following snippet in the function ieee80211_tx_prepare (mac80211/tx.c). if (is_multicast_ether_addr(hdr->addr1)) { tx->flags &= ~IEEE80211_TX_UNICAST; info->flags |= IEEE80211_TX_CTL_NO_ACK; } else { tx->flags |= IEEE80211_TX_UNICAST; if (unlikely(local->wifi_wme_noack_test)) info->flags |= IEEE80211_TX_CTL_NO_ACK; else info->flags &= ~IEEE80211_TX_CTL_NO_ACK; } So if you send a unicast frame without this wifi_wme_noack_test flag set then mac80211 will force the frame to require an ACK. To set the flag, # sudo -s "echo 1> /sys/kernel/debug/ieee80211/phy0/noack" Assuming phy0 is the wireless card with which you are wanting to do the frame injection. The downside to this is that now every frame is passed to ath9k with the no ack flag set. Daniel