Re: PATA port not detected when using AHCI on Intel 82801GB/GR/GH

[infernix <infernix@infernix.net>]

On 23/01/10 11:14, Alan Cox wrote:
>> Can we force ata_piix to pick up the IDE controller? I mean the old IDE
>> PIIX driver can do it (albeit terribly slow), so why can't ata_piix? I
>
> I doubt PIIX is doing it - the legacy IDE bits are.

You're right:

[    1.606687] Uniform Multi-Platform E-IDE driver
[    1.611276] ide_generic: please use "probe_mask=0x3f" module 
parameter for probing all legacy ISA IDE ports
[    1.908275] hda: TRANSCEND, CFA DISK drive
[    2.584069] ide0 at 0x1f0-0x1f7,0x3f6 on irq 14
[    3.156052] ide1 at 0x170-0x177,0x376 on irq 15

> What I think is going on is this (and I don't have docs so I am guessing)
>
> 	- The SOHO NAS has the IDE DOM wired to the LPC bus somewhere
> 	  directly (as legacy IDE)
> 	- The PATA port is intentionally disabled by the firmware to make
> 	  room for the DOM.
>
> In which case loading "pata_legacy" ought to make the right magic occur.

PATA_LEGACY Depends on: ATA [=y] && ATA_SFF [=y] && ISA [=n] && 
EXPERIMENTAL [=y]                                            │

So I have to turn on ISA for it to build. But that's not possible on 
x86_64 because it depends on X86_32. I'll try a 32bit build later, but 
I'd really like to be able to stay on x86_64. Is there a workaround?

> If that is the case I suspect the PIIX PATA port is not used at all
> by the sytstem (is it even wired to pins anywhere ?). If it is used then
> presumably the original NAS firmware does something truely hideous along
> the lines of
>
> -	Load boot image from DOM
> -	Turn off DOM/on PIIX
> -	Start using PIIX

Maybe I didn't make this clear enough, but the IDE DOM is not integrated 
in the NAS. I bought it afterwards and inserted it in the PATA port. I 
can just swap it for a 2.5" or 3.5" PATA harddisk if I want to.

Also, in both compatible and enhanced mode, the BIOS has no problem 
booting off the PATA port (with the IDE DOM that i bought). So I guess 
the bios may play some tricks here but when I boot off the PATA port in 
compatible mode, ata_piix is used to access the PATA port, and all is 
well with the world (except that I lose 2 SATA ports in compatible mode).

That would make me think it's actually wired to the ICH. Maybe also to 
the LPC bus but I'm not knowledgeable enough to know if thats even possible.