Am Tue, 31 Mar 2015 09:54:07 -0400 (EDT) schrieb Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>: > On Tue, 31 Mar 2015, Marc Joliet wrote: > > > > Like Matt suggested, the most reasonable possibility is an interaction > > > with the BIOS. > > > > Like I said in my replay to Matt, the BIOS doesn't support booting via USB. The > > If it supports a USB keyboard, it might still go through and initialize > all the USB devices. Hah! I should have thought of that. Well, I tried the following: unplug the drive before booting, plug it in once GRUB loads, and then boot the kernel. And guess what, *then* the drive works fine! I guess that *does* make it sound like the problem is due to interaction with the BIOS, combined with the weird block size translation. It seems as if the latter is done only once on device initialisation (though I'm curious: how can one determine whether it is necessary, that is, how can a USB drive detect whether it can advertise its true block size or not?). Now I wish that I had more systems to test with (e.g., with EFI). > > only thing I was able to try was to deactivate CD boot, which didn't change > > anything (except make boot faster, which is a nice side-effect, since I > > only very rarely boot from CD). > > > > I tried hooking it up to a borrowed laptop I have here (that only has USB 2 > > ports) to see how it behaves at boot. The BIOS was set to boot form its > > internal drive (followed by USB, but that would only trigger if the internal > > drive were missing, so it shouldn't have any influence, right? > > Impossible to tell. A BIOS can do anything it wants, whether it makes > sense or not. You'd have to monitor the USB bus to see what packets > were actually exchanged. > > To find out what the USB adapter is really doing, the best approach is > to ask the manufacturer -- since nobody else knows. The odds of > getting a useful reply are not high, unfortunately. I should have thought as much. -- Marc Joliet -- "People who think they know everything really annoy those of us who know we don't" - Bjarne Stroustrup
Attachment:
pgprKJvltCQsB.pgp
Description: Digitale Signatur von OpenPGP
