Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756223AbbBLONM (ORCPT ); Thu, 12 Feb 2015 09:13:12 -0500 Received: from mail-ob0-f176.google.com ([209.85.214.176]:39418 "EHLO mail-ob0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755702AbbBLONH (ORCPT ); Thu, 12 Feb 2015 09:13:07 -0500 MIME-Version: 1.0 In-Reply-To: <20150206135706.GB25683@amd> References: <20150205202527.GA7917@amd> <54D3F267.3000908@gmail.com> <20150206135706.GB25683@amd> From: Florian Fainelli Date: Thu, 12 Feb 2015 06:12:26 -0800 Message-ID: Subject: Re: Ethernet: how to disable gigabit support To: Pavel Machek Cc: kernel list , netdev Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1508 Lines: 38 2015-02-06 5:57 GMT-08:00 Pavel Machek : > On Thu 2015-02-05 14:44:55, Florian Fainelli wrote: >> On 05/02/15 12:25, Pavel Machek wrote: >> > Hi! >> > >> > This happened on more than one project: there's gigabit-capable chip, >> > but the connector is not designed for gigabit speed. >> > >> > I'd like to have speed autonegotiation, but not offer gigabit (as it >> > will not work). >> > >> > Is there way to do that without hacking the kernel? Should mii-tool do >> > that? >> >> Since you use the PHY library, you should be able to do something like >> this in your PHY driver prior to starting the PHY state machine: >> >> phydev->supported &= PHY_BASIC_FEATURES (effectively masking Gigabit >> capability) > > Thanks, that did the trick. > Pavel > (But still it would be nice to have a generic way of doing this, > using something like mii-tool.) You can also force that by setting the "max-speed" property in the Ethernet PHY node, the PHY library will populate the supported bitmask accordingly and remove speeds which are not supposed to be supported. I have to admit it has been a while since I used mii-tool, so the ioctl() side on the PHY library might be off. -- Florian -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/