From mboxrd@z Thu Jan 1 00:00:00 1970 From: Igor Plyatov Subject: Re: [PATCH v2] net: phy: workaround for buggy cable detection by LAN8700 after cable plugging Date: Fri, 14 Aug 2015 20:12:15 +0300 Message-ID: <55CE216F.6000806@gmail.com> References: <1439493514-10793-1-git-send-email-plyatov@gmail.com> <5164251.N6KMl6pkAR@kerker> <55CDA0B8.5000200@gmail.com> <3066235.RJEkKeJLOx@kerker> Reply-To: plyatov@gmail.com Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, f.fainelli@gmail.com, joe@perches.com, luwei.zhou@freescale.com, richardcochran@gmail.com, davem@davemloft.net, u.kleine-koenig@pengutronix.de, Fabio.Estevam@freescale.com, LW@karo-electronics.de, Frank.Li@freescale.com To: Michael Heimpold Return-path: In-Reply-To: <3066235.RJEkKeJLOx@kerker> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Dear Michael, > The LAN8700, LAN8710, LAN8720 is a product of the SMSC company. > Microchip acquired SMSC in August 2012. > > The LAN8700 is a legacy product for Microchip and they will not update > anything about it. So, even if Microchip know about HW bug, then there > is no chance to have Errata sheet or any new documents about LAN8700. > Long time ago, I worked on a custom device with a PHY of the same family. > Errata sheet existed but was only available by signing a NDA. So I simply > wondered whether this changed since SMSC is now Microchip or if they keep > it still so covered... The Microchip web-site does not contain Errata sheet for LAN87xx devices. While it contains many Errata sheets for PIC and dsPIC devices. So, situation is same as many years ago. > I propose following comment for the lan87xx_read_status(): > /* > * The LAN87xx suffers from rare absence of the ENERGYON-bit when > Ethernet cable > * plugs in while LAN87xx is in Energy Detect Power-Down mode. This > leads to > * unstable detection of plugging in Ethernet cable. > * This workaround disables Energy Detect Power-Down mode and waiting for > * response on link pulses to detect presence of plugged Ethernet cable. > * The Energy Detect Power-Down mode enabled again in the end of > procedure to > * save approximately 220 mW of power if cable is unplugged. > */ > Nice. Only one nitpick: ... _is_ enabled again... > Changed in [PATCH v3]. Best wishes. -- Igor Plyatov