Re: Kernel 2.6.30rc7 limits IDE to UDMA33

From: Alan Cox
Date: Sat Jun 06 2009 - 10:56:08 EST


> I wouldn't rule out the possibility of a bug. The code in pata_via looks
> a bit fishy, it reports a 40-wire cable if either the GTM data wasn't
> present or valid, or if it reports a mode of UDMA2 or less. In the
> former case it seems like ATA_CABLE_PATA_UNK would be the safer choice
> since we really don't know, and we should then use drive-side detection,
> rather than assuming a 40-wire cable by default..

Drive side detection doesn't work for many VIA boards, the neccessary
components are not included.

About the only other check I can think to try is to see if the BIOS
programmed modes > UDMA2 for either device. That has its own problems
(suspend-resume/hotplug/non-bios devices) which is why we currently don't
do it.

Alan
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