On Mon, Jun 11, 2007 at 08:11:24PM +0200, Andi Kleen wrote: > Matthew Garrett <[EMAIL PROTECTED]> writes: > > > BIOS authors don't always program all the features of hardware. This is > > often the case for Intel IDE controllers, which are usually able to run > > in AHCI mode but are rarely configured to do so. Reprogramming them is > > easy enough other than the requirement for some MMIO space. If the BIOS > > hasn't allocated this, it's necessary for us to do so manually. > > Traditionally we've had bad experiences forcing hardware to do something > the BIOS didn't consider. e.g. occasionally the BIOS has good reasons > to not allow it; maybe it knows about some errata or other problem > the kernel doesn't.
AHCI is generally disabled because it makes Windows insanely difficult to install. I'm not aware of any hardware issues in this case. > I tried something similar some time ago for the IOMMU aperture. > It turned out that some systems put something into the e820 holes > and didn't boot anymore if you put something else in there. > Your resource allocation will just do that. > > You might be lucky because your resources are typically > small (IOMMU aperture was 64+MB) or you might not. Hm. Yes, that would be a problem (sigh BIOS authors). -- Matthew Garrett | [EMAIL PROTECTED] - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
