Alex Buell wrote: > On Wed, 29 Apr 2009 22:27:46 -0400, I waved a wand and this message > magically appears in front of Jeff Garzik: > >> As Tejun noted, try switching to AHCI mode in BIOS. > > But is there a way to switch modes without needing to go through the > BIOS? Some laptops won't let you do that through BIOS. There is and it isn't too difficult either in itself but the problem is that for ahci mode to work the ABAR (PCI BAR 5) needs to be allocated and enabled. On x86, the kernel takes the PCI resources allocated by BIOS. Doing it directly isn't necessarily difficult but is too dangerous as there can be areas which aren't described anywhere but still are used by something. Because ICHs don't enable ABAR in piix mode unless SCRAE is set and most BIOSen don't set SCRAE, ABAR don't get allocated nor its space get reserved in most cases if the controller is in piix mode. So, at the point of driver load, there just isn't much we can do about the missing ABAR. It's sad. Dunno why some laptop manufacturers still program the thing into piix mode. :-( Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
