From: "Dale Farnsworth" <dale@farnsworth.org>
To: TSchnuerer@men.de, linuxppc-dev@ozlabs.org
Subject: Re: MPC5200 FEC Ethernet only halfduplex ?
Date: 3 Apr 2006 14:44:30 -0000 [thread overview]
Message-ID: <20060403144430.18964.qmail@farnsworth.org> (raw)
In-Reply-To: <0ABEEA3685414344B4BE536AE3912E6EC0506F@men-exch1.intra.men.de>
TSchnuerer@men.de wrote:
> Im working with Linux on our MPC5200 Board, with the latest Rev. B3
> Processor.
> I was updating our Linux BSP from BestComm 2.1 to 2.2 some time ago and
> used your patches which increased usability of the FEC very much.
>
> There is a line in the driver code which I dont understand, it says:
> + fec_restart(dev, 0); /* always use half duplex mode only */
>
> Why can only half duplex be used ?
The reason is simple, but not satisfying. The driver has no
mechanism to detect PHY status changes and thus no way to determine
when a connection changes from full to half duplex. It needs a
poll function for PHY status change. Doing only half-duplex
avoids this issue--at a big performance cost.
I think a poll function was added in the Denx version.
The MPC5200 FEC driver desperately needs a rewrite.
-Dale
prev parent reply other threads:[~2006-04-03 14:44 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-04-03 10:22 MPC5200 FEC Ethernet only halfduplex ? Thomas Schnürer
2006-04-03 14:44 ` Dale Farnsworth [this message]
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