From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Lunn Subject: Re: [PATCH 2/5] net: phy: hook up clause 45 autonegotiation restart Date: Thu, 1 Jun 2017 15:19:55 +0200 Message-ID: <20170601131955.GH9282@lunn.ch> References: <20170601102327.GF27796@n2100.armlinux.org.uk> <20170601122350.GA9282@lunn.ch> <20170601125132.GY22219@n2100.armlinux.org.uk> <20170601130527.GG9282@lunn.ch> <20170601130900.GA22219@n2100.armlinux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Florian Fainelli , netdev@vger.kernel.org To: Russell King - ARM Linux Return-path: Received: from vps0.lunn.ch ([178.209.37.122]:32823 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750952AbdFANT4 (ORCPT ); Thu, 1 Jun 2017 09:19:56 -0400 Content-Disposition: inline In-Reply-To: <20170601130900.GA22219@n2100.armlinux.org.uk> Sender: netdev-owner@vger.kernel.org List-ID: On Thu, Jun 01, 2017 at 02:09:00PM +0100, Russell King - ARM Linux wrote: > On Thu, Jun 01, 2017 at 03:05:27PM +0200, Andrew Lunn wrote: > > So you are saying a 10G PHY driver always needs to have a aneg_done > > callback, even if it just needs to call phygen_c45_aneg_done? > > > > This seems a bit error prone. I can see somebody writing a 10G driver, > > leaving out aneg_done() and having the c22 version called. Is the read > > of MII_BMSR likely to return 0xffff, since the register does not > > exist? If so, genphy_aneg_done() is likely to always return > > BMSR_ANEGCOMPLETE. > > Don't forget that the read will fail, so phy_read() will return a > negative number. By fail, you mean return something like -EIO or -ETIMEOUT? Is this guaranteed in the code somewhere? This particular Marvell PHY only does c45. But i could imagine some other PHYs answering a c22 request with 0xffff. Andrew