From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752804AbaCJAxk (ORCPT ); Sun, 9 Mar 2014 20:53:40 -0400 Received: from mail-ea0-f170.google.com ([209.85.215.170]:54373 "EHLO mail-ea0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752026AbaCJAxi (ORCPT ); Sun, 9 Mar 2014 20:53:38 -0400 Message-ID: <531D0D0D.4050703@gmail.com> Date: Mon, 10 Mar 2014 01:53:33 +0100 From: Sebastian Hesselbarth User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 To: David Miller CC: rob@landley.net, andrew@lunn.ch, f.fainelli@gmail.com, netdev@vger.kernel.org, linux-doc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] net: phy: Add sysfs attribute to prevent PHY suspend References: <531CF864.9040406@gmail.com> <20140309.203001.1318893833441564547.davem@davemloft.net> <531D094C.1090205@gmail.com> <20140309.204101.47552917508273123.davem@davemloft.net> In-Reply-To: <20140309.204101.47552917508273123.davem@davemloft.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/10/2014 01:41 AM, David Miller wrote: > From: Sebastian Hesselbarth > Date: Mon, 10 Mar 2014 01:37:32 +0100 > >> The mechanism is manual, no automatic way to determine it. > > We recognize BIOS and ACPI bugs and work around them, by looking at > version information and whatnot, so you really can't convince me that > something similar can't be done here perhaps in the platform code. Hmm, if the is a way to determine the version of that particual u-boot I'd be happy to exploit that information. But I honestly doubt that. Compared to u-boot bootloader and kernel interaction, BIOS and ACPI are well-defined protocols. I personally, would prefer everybody should update his broken bootloaders, but that will just not happen. Anyway, at least for the two boards in question, we know a bootloader workaround. The version does support user commands to re-enable the PHY by writing the corresponding registers. Unfortunately, the is a bug in phy_ethtool_get_wol that up to now, prevents most PHYs (without .wol callbacks) from being suspended. I wanted to get in a way to disable suspend before sending a fix. If you are that against a sysfs knob, I guess, we will just see how many more bootloaders are broken and some will not have a way to write PHY registers. Sebastian