Re: IDE/ATA: Intel i865-based mainboard, CDROM not detected

[Jeff Garzik]

Lennart Sorensen wrote:
> On Thu, May 31, 2007 at 10:21:57AM +0930, Jonathan Woithe wrote:
> > I don't think so but I could be wrong.  When "Configure SATA as" was set to
> > "IDE" the HDD was being detected as a SATA drive and showed up as /dev/sda. 
> > The only visible difference the change to "AHCI" made was that instead of
> > the drive being handled by the ata_piix it now utilises the ahci driver
> > (which is a much better driver).  The other interesting thing is that the
> > probe for the Marvell PATA device occured before the initialisation of the
> > ata_piix driver (or ahci for that matter), so as far as I can tell ata_piix
> > had no chance to grab any ports before the marvell driver initialised.
>
> Linux can still detect the chip and drive it natively even if the bios
> is emulating IDE/PATA on the chip.  And libata will make both PATA and
> SATA show up as /dev/sda now if you use libata for both.  On the other
> hand if the bios has configured the intel chip to use the standard ide
> registers, then it can't have configured the marvell to do so I would
> guess, which could make it difficult to talk to.

Mostly true...  "standard IDE" can be configured in two modes, legacy 
mode and native mode.  Legacy mode has fixed addresses originating from 
the ISA days (0x170, 0x1f0, irqs 14 & 15), and (as you implied) you 
cannot bind two IDE controllers to the same ISA addresses.

OTOH, an unlimited number of IDE controllers can be configured into 
native mode, where all addresses and irq are allocated using standard 
means accorded all PCI devices.

	Jeff



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