linux-kernel - RE: [PATCH v4] lxt PHY: Support for the buggy LXT973 rev A2

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <AE90C24D6B3A694183C094C60CF0A2F6026B7004@saturn3.aculab.com>
Date:	Mon, 24 Sep 2012 15:13:41 +0100
From:	"David Laight" <David.Laight@...LAB.COM>
To:	"Christophe Leroy" <christophe.leroy@....fr>,
	"David S Miller" <davem@...emloft.net>,
	"Richard Cochran" <richardcochran@...il.com>
Cc:	<netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH v4] lxt PHY: Support for the buggy LXT973 rev A2

> This patch adds proper handling of the buggy revision A2 of LXT973 phy, adding
> precautions linked to ERRATA Item 4:
> 
> Revision A2 of LXT973 chip randomly returns the contents of the previous even
> register when you read a odd register regularly

Does reading the PHY registers involve bit-banging an MII interface?
If so this code is likely to stall the system for significant
periods (ready phy registers at all can be a problem).

I know some ethernet mac have hardware blocks for reading MII
and even polling one MII register for changes.

Maybe some of this code ought to be using async software
bit-bang - especially when just polling for link status change.
I'm sure it ought to be possible to do one bit-bang action
per clock tick instead of spinning for the required delays. 

	David

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/