Re: 2.6.20 libata cdrom

[William Thompson <wt@electro-mechanical.com>]

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?