Re: 2.6.20 libata cdrom

From: William Thompson
Date: Tue May 01 2007 - 13:21:38 EST


On Tue, May 01, 2007 at 03:40:36PM +0200, Tejun Heo wrote:
> >> Tejun, don't we have a fallback for when IDENTIFY fails?
> >> If the drive rejects it (err=0x04), then this can mean only one thing:
> >> unsupported command, so we next must try PACKET_IDENTIFY.
>
> Up until now, we've been depending on the device giving us the correct
> signature on reset. This is the first reported case which screws that
> up. Gee... Two crazy screwed up devices today. What's going on?

libata-pata is getting it's field testing now!

> > Is it doing that just for this drive? I use libata on another machine (Dell
> > Dimension 2400) and it finds the cdrom just fine.
>
> That specific cdrom is crazy. It's telling libata that it's a disk when
> it apparently isn't.

Wasn't sure, I thought it was something with the chipset. Every Dell
Dimension L series machine has done this to me (The DMA thing, that is).
Some gateways have as well.

> > The one thing I do know, the machine with the non-working libata cdrom also
> > does not work with the ide driver *ONLY IF* DMA is turned on.
>
> This is probably as Mark explained in the other thread.
>
> Anyways, oh well, it looks like we need fallback mechanism to the other
> IDENTIFY command after all. Jeff, any ideas or objections?

Got a patch or anything I can do to test?
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