Re: !!Warning!! UDMA and Fujitsu HD

Jamie Lokier (lkd@tantalophile.demon.co.uk)
Tue, 4 Aug 1998 13:25:24 +0100


On Tue, Aug 04, 1998 at 11:25:17AM +0200, Peter T. Breuer wrote:
> "A month of sundays ago Jamie Lokier wrote:"
> > Please note I am using a VIA VP2/97-based motherboard (the FIC PA-2007),
> > and I _have_ to use -X34 otherwise UDMA locks up my machine within a few
>
> ?? Do you mean that the board does udma automatically and that the
> kernel lets it (ide0=autotune) and that then you turn off udma on the
> disk, but not on the board ...

Oh, I didn't realise -X34 turned _off_ UDMA. In fact I thought maybe it
turned it on on the drive!

So what's the option to turn it on?

> .. and that doesn't hurt? It's precisely what did lock my BX system.

I copied someone else who did something similar. Can't remember if it
was bad or not {:-)} but it inspired me and it seems to have fixed my
problem while getting me the same speeds as without it and DMA enabled.

Unless, of course, UDMA is even faster than anything I've measured so
I've never had UDMA running. (I'm getting about 9.2MB/sec from my
Quantum FB ST 6.4Gig).

> Won't "ide0=noautotune" do?

For a long while I had to use "ide0=nodma".
Now I don't need it, I just do -X34 during a boot script.

What would "ide0=noautotune" do?

It could lock up during the boot process before the script, but I don't
boot often enough to find out (now that the lockups don't seem to
happen...)

> One lesson is that the ide boot parameters should be less crytic!
> "ide0=udma" maybe? And hdparm needs a little extension too.

And somewhere something could give me a clue what my system thinks it is
now doing!

-- Jamie

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