From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arthur Jones Subject: Re: [PATCH] e1000e: workaround missing power down mii control bit on 82571 Date: Thu, 16 Dec 2010 14:14:21 -0800 Message-ID: <20101216221421.GR18990@ajones-laptop.nbttech.com> References: <20101216182847.GA14985@ajones-laptop.nbttech.com> <1292525797.3253.8.camel@bwh-desktop> <8DD2590731AB5D4C9DBF71A877482A9001773F7655@orsmsx509.amr.corp.intel.com> <8DD2590731AB5D4C9DBF71A877482A9001773F76C4@orsmsx509.amr.corp.intel.com> <20101216200425.GO18990@ajones-laptop.nbttech.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Cc: Ben Hutchings , "Kirsher, Jeffrey T" , "netdev@vger.kernel.org" To: "Allan, Bruce W" Return-path: Received: from smtp2.riverbed.com ([208.70.196.44]:39274 "EHLO smtp2.riverbed.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753572Ab0LPWOW (ORCPT ); Thu, 16 Dec 2010 17:14:22 -0500 Content-Disposition: inline In-Reply-To: <20101216200425.GO18990@ajones-laptop.nbttech.com> Sender: netdev-owner@vger.kernel.org List-ID: Hi Bruce, ... On Thu, Dec 16, 2010 at 12:04:26PM -0800, Arthur Jones wrote: > Hi Bruce, ... > > On Thu, Dec 16, 2010 at 11:28:18AM -0800, Allan, Bruce W wrote: > > >-----Original Message----- > > >From: netdev-owner@vger.kernel.org [mailto:netdev-owner@vger.kernel.org] On > > >Behalf Of Allan, Bruce W > > >Sent: Thursday, December 16, 2010 11:04 AM > > >To: Ben Hutchings; Arthur Jones > > >Cc: Kirsher, Jeffrey T; netdev@vger.kernel.org > > >Subject: RE: [PATCH] e1000e: workaround missing power down mii control bit on > > >82571 > > > > > >>-----Original Message----- > > >>From: netdev-owner@vger.kernel.org [mailto:netdev-owner@vger.kernel.org] On > > >>Behalf Of Ben Hutchings > > >>Sent: Thursday, December 16, 2010 10:57 AM > > >>To: Arthur Jones > > >>Cc: Kirsher, Jeffrey T; netdev@vger.kernel.org > > >>Subject: Re: [PATCH] e1000e: workaround missing power down mii control bit on > > >>82571 > > >> > > >>Adding this special case into MDIO access seems like a really nasty > > >>hack. Surely the callers that set the control register should take care > > >>of this. > > >> > > >>Ben. > > > > > >Agreed. I am setting up to repro now to see if it is an actual hardware > > >issue or just a software bug; either way, this patch is not the correct > > >approach and I'll follow up shortly. > > > > > >Bruce. > > > > It's the reset in e1000_set_settings() which ignores that we had previously > > powered off the Phy. I'll go through the rest of the code and fix up this > > and any other occurrences of similar issues properly. > > Thanks for having a look! > > We do a read-modify-write there of > the PHY control register. We take > the rest of the bits as being good, > but, for some reason we don't get the > power down bit (always reads back > zero). Is this a known 82571 issue? > On 82574, e.g., we seem to get the > power down bit back when we read... BTW: The 802.3 spec seems to indicate that this bit _should_ be readable even when the PHY is powered down (i.e. this is a PHY bug)... Arthur > > Are you sure you want to spread that > 82571 specific logic all over the driver? > > Arthur > > > > > Thanks for reporting this issue Arthur. > > > > Bruce.