Re: HPET enabled in BIOS, not presented as available_clocksource -- config, kernel code, &/or BIOS?

From: Randy Dunlap
Date: Sat May 13 2017 - 15:31:48 EST


On 05/13/17 11:26, PGNet Dev wrote:
> On 5/13/17 10:41 AM, Randy Dunlap wrote:
>> [adding HPET driver maintainer]
>
> Thanks
>
>> A couple of comments below...
>
>>> In BIOS, HPET's enabled.
>>
>> How about if you just boot Linux without Xen? Does HPET show up then?
>
> yes, it appears so:
>
> cat devices/system/clocksource/clocksource0/available
> tsc hpet acpi_pm

Adding xen mailing list:

Is HPET support a known issue in Xen?

release : 4.11.0-4.gcb15206-default
xen_version : 4.9.0_04-493


Original message is here:
http://marc.info/?l=linux-kernel&m=149464267427111&w=2


Thanks.

>>> [ 8.491738] hpet_acpi_add: no address or irqs in _CRS
>>
>> Above line marks a big failure. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
> I suspected that's problematic.
>
> In the non-Xen case
>
> dmesg | grep -i hpet
> [ 0.000000] ACPI: HPET 0x000000009E8298F8 000038 (v01 SUPERM SMCI--MB 01072009 AMI. 00000005)
> [ 0.000000] ACPI: HPET id: 0x8086a701 base: 0xfed00000
> [ 0.000000] clocksource: hpet: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 133484882848 ns
> [ 0.000000] hpet clockevent registered
> [ 0.144010] DMAR-IR: HPET id 0 under DRHD base 0xfed90000
> [ 1.398047] hpet0: at MMIO 0xfed00000, IRQs 2, 8, 0, 0, 0, 0, 0, 0
> [ 1.404226] hpet0: 8 comparators, 64-bit 14.318180 MHz counter
> [ 1.412080] clocksource: Switched to clocksource hpet
> [ 3.627234] rtc_cmos 00:02: alarms up to one month, y3k, 242 bytes nvram, hpet irqs
>


--
~Randy