Subject: Re: problems assessing disk size with ahcisata
To: Steven M. Bellovin <>
From: Arto Huusko <>
List: current-users
Date: 11/05/2007 08:34:48
Steven M. Bellovin wrote:
> I just ran into a serious problem with a new Thinkpad T61: anything
> looking at the MBR on the 160G disk running with ahcisata got very
> confused.  I'll skip all the gory details (and the state it left my
> disk in); the net, though, is the fdisk and sysinst think the drive has
> only 67MB.  When I changed it in the BIOS to compatibility mode, it
> picked up the size correctly.

I've seen this behaviour on T61 too, but the way the disk is probed
seems to depend on what order devices are probed and attached:
tweaking unrelated things in kernel config make or break the disk

I guess there is some delay or interrupt issue with the disk probed:
when the disk is probed wrong, there is a noticeable delay in kernel
messages, and often some other device attaches in the middle of
disk attachment.

Anyway, for what ever reason, attachment of pckbc fixes or breaks
the disk probe for me: with pckbc at isa disk is fine, with pckbc
at acpi it is not.