On Thu, Sep 29, 2011 at 12:46:18PM -0700, Randy Dunlap wrote: > On 09/29/11 11:50, Greg KH wrote: > > On Thu, Sep 29, 2011 at 08:44:26PM +0200, Christian Schaubschläger wrote: > >> > >>>> Enabling ACPI is not an option for me in that case. > >>> Why not? > >> > >> Well, the reason is the following: > >> After starting the linux system I switch back the machine to real mode > >> using the kexec system call (then I run some real/protected mode stuff). > >> This works fine in most cases, but on some machines after kexec the > >> machine is in a state where important things (eg. some bios interrupt > >> calls) don't work any more. The reason for that is that the machine's > >> interrupt controller/pci system/chipset is left in an 'unusable' state > >> by the ACPI system... > >> > >> Disabling ACPI solved this issue on almost all machines; however, > >> recently I had to deal with some machines with usb3, and on some of them > >> I observed the behaviour I described before. > >> > >> Now I'm aware that this is not the typical usage scenario of a linux > >> system, and I'm also aware that another option to get things working in > >> real mode again would be trying to re-configure (or reset) the hardware > >> after kexec; but this is not a trivial thing to do; for me it would be > >> easiest to have xhci working without ACPI. That's why I was asking. > > > > Again, this isn't a xhci issue, ACPI is in charge of handling the PCI > > irq routing here, so it is needed to have the pci devices work properly. > > > > I suggest you work with the Linux ACPI developers to solve your problem, > > and that will then resolve the xhci issue as well. > > so (for arch/x86/Kconfig), this: > > config PCI > bool "PCI support" > default y > select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC) > > should also say: > select ACPI > or > depends on ACPI > > I hope not. No, but for this motherboard, it looks like yes, ACPI is required to get PCI interrupt routing correct. It's been that way for a few years now on a lot of different boards, nothing new here at all. > I do think it would be worthwhile to discuss this (xhci) problem > with the kexec people. I think it would make more sense to discuss the acpi issue with the kexec people... greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
