From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E7E665694 for ; Thu, 13 Jul 2023 06:31:08 +0000 (UTC) Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 07B6F12E for ; Wed, 12 Jul 2023 23:31:05 -0700 (PDT) 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=MQfjjMpqp7jEqgrQCjtU6VfkjlrDkn+UAqPM/menHHk=; b=jenrW412yHYlCAv1XIv0vICcPa jT8blcKIHfMoN90Xu7ShDFEbrWHtCbPrFvFOqjzxKYnFIXZfEDFmKGuOzoP6WqiseBVjowm8szpcS lLAz2Y7Mk8wLhqsGOhdFn1Vo9D9u6bQj8Bmg0+3AQpJziVtQxJNQg/J2C7mlN0745yhS9JjP8qkf1 HJdDdsJ6+VXBvLY2YlAF8VOw7GuXvfoFC5M2B37e0J5SJU6wlIi4wqEModPonUfbhc0RFgvRsenIV 2DPeT3cK2oK15OoDNKqHuixk3k+N2wbu1o5sCXDQTM2jnz3Vuz01nzMFOUsvm77t2/0kpl7OY2TeX uL4yxxfg==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:47516) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1qJpqw-0005k4-2S; Thu, 13 Jul 2023 07:31:02 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1qJpqv-0005sp-6Q; Thu, 13 Jul 2023 07:31:01 +0100 Date: Thu, 13 Jul 2023 07:31:01 +0100 From: "Russell King (Oracle)" To: Stefan Eichenberger Cc: netdev@vger.kernel.org, andrew@lunn.ch, hkallweit1@gmail.com, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, francesco.dolcini@toradex.com Subject: Re: [PATCH v1 2/2] net: phy: marvell-88q2xxx: add driver for the Marvell 88Q2110 PHY Message-ID: References: <20230703124440.391970-1-eichest@gmail.com> <20230703124440.391970-3-eichest@gmail.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230703124440.391970-3-eichest@gmail.com> Sender: Russell King (Oracle) X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_BLOCKED, SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net On Mon, Jul 03, 2023 at 02:44:40PM +0200, Stefan Eichenberger wrote: > +static int check_link(struct phy_device *phydev) > +{ > + u16 ret1, ret2; > + > + if (phydev->speed == SPEED_1000) { > + ret1 = phy_read_mmd(phydev, 3, 0x0901); > + ret1 = phy_read_mmd(phydev, 3, 0x0901); This looks like some kind of BMSR register, where the link status latches on failure until the following read. By reading the register twice, you are discarding the information that the link _had_ failed since we last read it. You don't want to do that - it could come up with different parameters and because the link to phylib appears to remain up, it won't respond to the new link parameters. Always report the latched link status, not the current status. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!