Messages in this thread | | | Date | Fri, 28 Mar 2014 15:37:18 +0800 | From | Feng Tang <> | Subject | Re: [PATCH v2] x86: hpet: Don't default CONFIG_HPET_TIMER to be y for X86_64 |
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Hi Ingo,
Thanks for reviewing this
On Fri, Mar 28, 2014 at 08:17:16AM +0100, Ingo Molnar wrote: > > * Feng Tang <feng.tang@intel.com> wrote: > > > On many new phone/tablet platforms like Baytrail/Merrifield etc, the > > HPET are either defeatured or has some problem to be used as a > > reliable timer. As these platforms also have X86_64, we should not > > make HPET_TIMER default y for all X86_64. > > NAK! > > If the HPET is unreliable on a specific platform then any of the > following solutions would address the problem (in order of > preference): > > - the hardware should not expose it. Why waste silicon on something > that does not work? > > - or the firmware should not expose it. Why expose something that > does not work?
Agreed, I've raised problem to BIOS vendor, but the response is very slow, and those hardware/BIOS may already hit the market as a product.
> > - 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, only thing I can think of to identify them may be the CPU family/ID. Runtime check the reliability of HPET may be difficult, as we don't know if the 8254 or the TSC are the golden timer to check HPET.
Thanks, Feng
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