On Monday 27 April 2009 02:15:33 pm Yinghai Lu wrote: > Bjorn Helgaas wrote: > > On Monday 20 April 2009 07:35:40 pm Yinghai Lu wrote: > >> it wil be overwriten later if _CRS is used, so don't bother to set it. > >> > >> [ Impact: cleanup ] > >> > >> Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx> > >> > >> --- > >> arch/x86/pci/amd_bus.c | 4 ++++ > >> 1 file changed, 4 insertions(+) > >> > >> Index: linux-2.6/arch/x86/pci/amd_bus.c > >> =================================================================== > >> --- linux-2.6.orig/arch/x86/pci/amd_bus.c > >> +++ linux-2.6/arch/x86/pci/amd_bus.c > >> @@ -100,6 +100,10 @@ void x86_pci_root_bus_res_quirks(struct > >> int j; > >> struct pci_root_info *info; > >> > >> + /* don't go for it if _CRS is used */ > >> + if (pci_probe & PCI_USE__CRS) > >> + return; > >> + > >> /* if only one root bus, don't need to anything */ > >> if (pci_root_num < 2) > >> return; > > > > This isn't a comment on this patch per se. > > > > I am concerned about the fact that "pci=use_crs" is not the default. > > From the changelog of 62f420f8282, it sounds like you have to boot an > > IBM x3850 with "pci=use_crs" to make hot-plug work, even though ACPI > > tells us everything we need to know. That's backwards. > > > > We shouldn't need an option to tell Linux that the firmware is > > trustworthy. We should have an option to *ignore* it for the times > > when we trip over something broken and haven't figured out a way to > > work around it yet. > > other system may have broken _CRS. Do you have examples of problems here, or are you just worried that there *may* be problems? > maybe we could try to use DMI whitelist them? I don't like a whitelist because it requires ongoing maintenance for correctly-working machines. A blacklist is nicer because it only requires maintenance for *broken* machines. A date-based solution would be better from that point of view. Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
