Re: [PATCH] ACPI driver support for pata

From: Jeff Garzik
Date: Thu Feb 22 2007 - 01:59:22 EST

Robert Hancock wrote:
Alan wrote:
- Add a driver for motherboard ACPI method devices
- Link it after normal drivers so ACPI is not preferred
- Hook the AMD driver to prefer ACPI for the Nvidia devices if ACPI is
- While we are at it fix up the simplex clear the AMD driver.

Depends upon the set_mode -> do_set_mode wrapper patch

Signed-off-by: Alan Cox <alan@xxxxxxxxxx>

I tried out 2.6.21-rc1 with the pata_acpi patch. First off, when you enable pata_acpi, it appears that the Fedora mkinitrd stuff decides that that should be loaded as the first driver. On boot it promptly attempts to attach to all of the ATA controllers, including the nForce SATA controllers, which somehow it fails to actually drive causing a failure to mount the root filesystem. I got around that by blacklisting pata_acpi in /etc/modprobe.conf before installing the kernel and un-blacklisting it afterwards, so it wouldn't make the initrd try and load it, but there must be a better solution.

It does seem to drive the PATA controllers, but the cable detection doesn't seem to be working:

scsi5 : pata_acpi
ata5.00: ATAPI, max UDMA/66
ata5.00: limited to UDMA/33 due to 40-wire cable
ata5.00: configured for UDMA/33

Honestly I don't think pata_acpi is the best way to go.

Unless we know /nothing/ about the controller (not true, in sata_nv case), I think it would be better to initiate ACPI actions from specific drivers, rather than forcing the user to switch from pata_amd to pata_acpi.


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