Hi Ingo, On Fri, Mar 28, 2014 at 09:11:17AM +0100, Ingo Molnar wrote: > > * Clemens Ladisch <clem...@ladisch.de> wrote: > > > Feng Tang wrote: > > > On Fri, Mar 28, 2014 at 08:17:16AM +0100, Ingo Molnar wrote: > > >> * Feng Tang <feng.t...@intel.com> wrote: > > >> - or the kernel should have a quirk to reliably disable it. Why > > >> should we crash or misbehave if a driver is built into the > > >> kernel? > > > > > > I thought about this before, HPET doesn't have PCI ID like stuff, > > > > HPET does have the PCI vendor ID in the first register. > > > > > only thing I can think of to identify them may be the CPU family/ID. > > > > The HPET is implemented by some actual chip, and that chip also has lots > > of PCI devices. (In the case of a SoC, the CPU ID would work, too). > > Correct. See arch/x86/kernel/hpet.c, which has a large number of HPET > quirks keyed off chipset PCI IDs: > > DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB2_0, > ich_force_enable_hpet); > DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ICH6_0, > ich_force_enable_hpet); > DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ICH6_1, > ich_force_enable_hpet); > [...]
I just gave it another thought, that the HPET on our platform currently do have some problem to be used as clocksource/clockevent, but it may get fixed in future version (by Silicon or BIOS). If I add quirk to block it now, I may revert this code in future when it get fixed, same problem applis for the future generation of platform. So can we do a small change like below, so that we are able to disable the HPET_TIMER in our own x86_64 .config, while all exising distributions are not affected as it is still default "y" . --- diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index f67e839..a1027a5 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -711,7 +711,7 @@ source "arch/x86/Kconfig.cpu" config HPET_TIMER def_bool X86_64 - prompt "HPET Timer Support" if X86_32 + prompt "HPET Timer Support" ---help--- Use the IA-PC HPET (High Precision Event Timer) to manage time in preference to the PIT and RTC, if a HPET is Thanks, Feng -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/