From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH (net.git)] stmmac: prevent false carrier sense detection Date: Fri, 29 Aug 2014 19:55:39 -0700 (PDT) Message-ID: <20140829.195539.1489311917586365339.davem@davemloft.net> References: <1409120404-20414-1-git-send-email-peppe.cavallaro@st.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: peppe.cavallaro@st.com Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:52481 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750898AbaH3Czm (ORCPT ); Fri, 29 Aug 2014 22:55:42 -0400 In-Reply-To: <1409120404-20414-1-git-send-email-peppe.cavallaro@st.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Giuseppe Cavallaro Date: Wed, 27 Aug 2014 08:20:04 +0200 > This patch is to w/a a problem that happens on some boxes when run at 10Mbps > Half duplex mode. > > During the transmission the CSR signal is asserted for some time and the frames > aborted because of carrier sense error. > This is reported by MMC HW counter: txcarrier signal. > This actually is a false carrier so the frames are good and there is no reason > to ask for dropping them. > > This patch so disables the Carrier Sense During Transmission > and this means that the MAC transmitter ignore the CRS signal > during frame transmission in Half-Duplex mode. > > Signed-off-by: Giuseppe Cavallaro > Acked-by: Vince Bridgers > Acked-by: Ley Foon Tan > Acked-by: Chen-Yu Tsai Applied. Although it would have made more sense to me if you only set the DCRS bit in the case where the troubles occur, half-duplex 10Mbps, so that in other modes real carrier loss during transmit would actually be detected.