From: Igor Plyatov <plyatov@gmail•com>
To: Michael Heimpold <mhei@heimpold•de>
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
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 [thread overview]
Message-ID: <55CE216F.6000806@gmail.com> (raw)
In-Reply-To: <3066235.RJEkKeJLOx@kerker>
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
prev parent reply other threads:[~2015-08-14 17:12 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-13 19:18 [PATCH v2] net: phy: workaround for buggy cable detection by LAN8700 after cable plugging Igor Plyatov
[not found] ` <5164251.N6KMl6pkAR@kerker>
2015-08-14 8:03 ` Igor Plyatov
2015-08-14 16:31 ` Michael Heimpold
2015-08-14 17:12 ` Igor Plyatov [this message]
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