From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1AD4AC432C0 for ; Fri, 22 Nov 2019 15:19:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E10D12071B for ; Fri, 22 Nov 2019 15:19:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="CSwvWC29" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726767AbfKVPTS (ORCPT ); Fri, 22 Nov 2019 10:19:18 -0500 Received: from pandora.armlinux.org.uk ([78.32.30.218]:46860 "EHLO pandora.armlinux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726045AbfKVPTR (ORCPT ); Fri, 22 Nov 2019 10:19:17 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=pMD8odOMs/KFtDYCt/r1bWIrjWCUci9BNgccikQ8rgA=; b=CSwvWC29apy9LZj3zuZ/HauHi DEWLcdRfndF30CkUuPi+8CPdS7sXNMW2VAoD8TIzERK89k7NGVdPiBuyH9jlnPH37S9QyszpJEzO8 2fwuDcnYn1GcItlQlYJVMIkV7O1KkAkfVknZ6zAgQ8E/UqjPxZ9EJO0uUNIV1GOTc3GzUkGw/uVVo BbSBQiozYGj9Mp9FsDa371hh7D5nCkczw+CNO5jZtJpoErdFZQUTUQ6K7pkbIuiM31Ct0OJc/Jk1v lJsn6bJCvRsmYOJmHZS5Tfys4SsXe7uOxHv2gDJnMA0EIXQOj7hp+/NQPqfqnOnin4bJHxwc0Delb BNhF8EQ6A==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:43164) by pandora.armlinux.org.uk with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1iYAiF-0005ug-LO; Fri, 22 Nov 2019 15:19:11 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.92) (envelope-from ) id 1iYAiC-0003qg-W8; Fri, 22 Nov 2019 15:19:09 +0000 Date: Fri, 22 Nov 2019 15:19:08 +0000 From: Russell King - ARM Linux admin To: Andrew Lunn , Florian Fainelli , Heiner Kallweit Cc: "David S. Miller" , netdev@vger.kernel.org Subject: Re: [RFC] net: phy: allow ethtool to set any supported fixed speed Message-ID: <20191122151908.GK25745@shell.armlinux.org.uk> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, Nov 22, 2019 at 03:18:10PM +0000, Russell King wrote: > phylib restricts the fixed speed to 1000, 100 or 10Mbps, even if the > PHY supports other speeds, or doesn't even support these speeds. > Validate the fixed speed against the PHY capabilities, and return an > error if we are unable to find a match. > > Signed-off-by: Russell King > --- > NOTE: is this correct behaviour - or should we do something like: > > s = phy_lookup_setting(speed, duplex, phydev->support, false); > if (!s) > return -EINVAL; > > phydev->speed = speed; > phydev->duplex = duplex; Sorry, that should've been: phydev->speed = s->speed; phydev->duplex = s->duplex; > > IOW, set either an exact match, or a slower supported speed than was > requested, or the slowest? That's how phy_sanitize_settings() is > implemented, which I replicated for phylink's ethtool implementation. > > Another issue here is with the validation of the settings that the > user passed in - this looks very racy. Consider the following: > > - another thread calls phy_ethtool_ksettings_set(), which sets > phydev->speed and phydev->duplex, and disables autoneg. > - the phylib state machine is running, and overwrites the > phydev->speed and phydev->duplex settings > - phy_ethtool_ksettings_set() then calls phy_start_aneg() which > sets the PHY up with the phylib-read settings rather than the > settings the user requested. > > IMHO, phylib needs to keep the user requested settings separate from > the readback state from the PHY. > > Yet another issue is what to do when a PHY doesn't support disabled > autoneg (or it's not known how to make it work) - the PHY driver > doesn't get a look-in to validate the settings, phylib just expects > every PHY out there to support it. The best the PHY driver can do > is to cause it's config_aneg() method to return -EINVAL, dropping > the PHY state machine into PHY_HALTED mode via phy_error() - which > will then provoke a nice big stack dump in phy_stop() when the > network device is downed as phy_is_started() will return false. > Clearly not a good user experience on any level (API or kernel > behaviour.) > > drivers/net/phy/phy.c | 29 +++++++++++++++-------------- > 1 file changed, 15 insertions(+), 14 deletions(-) > > diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c > index 9e431b9f9d87..75d11c48afce 100644 > --- a/drivers/net/phy/phy.c > +++ b/drivers/net/phy/phy.c > @@ -270,31 +270,32 @@ int phy_ethtool_ksettings_set(struct phy_device *phydev, > linkmode_and(advertising, advertising, phydev->supported); > > /* Verify the settings we care about. */ > - if (autoneg != AUTONEG_ENABLE && autoneg != AUTONEG_DISABLE) > - return -EINVAL; > + switch (autoneg) { > + case AUTONEG_ENABLE: > + if (linkmode_empty(advertising)) > + return -EINVAL; > + break; > + > + case AUTONEG_DISABLE: > + if (duplex != DUPLEX_HALF && duplex != DUPLEX_FULL) > + return -EINVAL; > > - if (autoneg == AUTONEG_ENABLE && linkmode_empty(advertising)) > - return -EINVAL; > + if (!phy_lookup_setting(speed, duplex, phydev->supported, true)) > + return -EINVAL; > + break; > > - if (autoneg == AUTONEG_DISABLE && > - ((speed != SPEED_1000 && > - speed != SPEED_100 && > - speed != SPEED_10) || > - (duplex != DUPLEX_HALF && > - duplex != DUPLEX_FULL))) > + default: > return -EINVAL; > + } > > phydev->autoneg = autoneg; > - > + phydev->duplex = duplex; > phydev->speed = speed; > > linkmode_copy(phydev->advertising, advertising); > - > linkmode_mod_bit(ETHTOOL_LINK_MODE_Autoneg_BIT, > phydev->advertising, autoneg == AUTONEG_ENABLE); > > - phydev->duplex = duplex; > - > phydev->mdix_ctrl = cmd->base.eth_tp_mdix_ctrl; > > /* Restart the PHY */ > -- > 2.20.1 > > -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up According to speedtest.net: 11.9Mbps down 500kbps up