On Fri, Apr 9, 2010 at 10:37 AM, Tim Small <tim@xxxxxxxxxxxxxxxx> wrote: > Alan Cox wrote: >>> Some laptop BIOSes do try to access the controller at certain points, >>> like suspend or powerdown (presumably to make sure the drive heads are >>> unloaded or something) - we've run into problems in the past when the >>> controller was disabled at points where the BIOS didn't expect it to >>> be and it was trying to poke at it, causing a big delay until it >>> finally gave up. >>> >> >> >> Suspend/powerdown are less of a problem because any patch to put it into >> AHCI mode should put it back as it was before during suspend/poweroff. >> > > Using DECLARE_PCI_FIXUP_SUSPEND etc? I'll see if I can get some time to > have a go at this. The hardware I have access to without AHCI BIOS > options are Dell Poweredge R200s and R300s. Yeah, you'll really want to enable AHCI mode in the header stage on boot and on resume, and disable it on suspend and shutdown (not sure if we actually have a hook for the shutdown case?) > > As far as I can workout, from my experiments using setpci+fakehp two of > the port IO regions get coalesced, and an additional memory IO BAR gets > set up on the ICH9R when in AHCI mode, so I'll have to try and work out > how to handle this properly in the quirk. > > As Robert said, the "off-by-default + if it breaks, you get to keep both > pieces" policy is what I had in mind, and I think this should go into > arch/x86/pci/fixup.c ? Any obvious pit-falls to avoid? We seem to have most related quirks for this in drivers/pci/quirks.c, but I guess it could go into either.. -- 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
