Re: [PATCH v2] lxt PHY: Support for the buggy LXT973 rev A2

On Sat, Sep 22, 2012 at 06:21:38PM +0200, leroy christophe wrote:

Le 10/09/2012 20:17, Lutz Jaenicke a écrit :

quoted

On Mon, Sep 10, 2012 at 05:45:49PM +0200, Christophe Leroy wrote:

quoted

This patch adds proper handling of the buggy revision A2 of LXT973 phy, adding
precautions linked to ERRATA Item 4:

Item 4: MDIO Interface and Repeated Polling
Problem: Repeated polling of odd-numbered registers via the MDIO interface
randomly returns the contents of the previous even register.
Implication: Managed applications may not obtain the correct register contents
when a particular register is monitored for device status.
Workaround: None.
Status: This erratum has been previously fixed (in rev A3)

Hmm. Were did you get the hardware from? We have been using LXT973 in
our products and the A2 was replaced by A3 in 2003.

Best regards,
Lutz

They are custom boards that my company manufactures. Most boards
manufactured before 2006 or 2007 have this buggy chip.

Ok, so this problem indeed is related to (very) old hardware.
I would not be sure whether the hack needed to work around
this bug should be added one decade after the chip has
been fixed.

Best regards,
	Lutz
PS.Yes, we have used the same workaround with such hardware, fortunately
we only had a few first boards using A2 and the series production
started just with A3 at that time.
-- 
Dr.-Ing. Lutz Jänicke
CTO
Innominate Security Technologies AG  /protecting industrial networks/
tel: +49.30.921028-200
fax: +49.30.921028-020
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D-12489 Berlin, Germany
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