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

From: Clemens Ladisch
Date: Sat May 13 2017 - 15:56:49 EST


Randy Dunlap wrote:
> On 05/12/17 19:30, PGNet Dev wrote:
>> dmesg | grep -i hpet
>> [ 8.491738] hpet_acpi_add: no address or irqs in _CRS
>
> Above line marks a big failure. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
>> Disassembling the firmware acpi tables
>>
>> cat /sys/firmware/acpi/tables/HPET > /var/tmp/hpet.out
>> iasl -d /var/tmp/hpet.out

That table is not used by hpet_acpi_add; you have to check for the device
that mentions "PNP0103" in the DSDT table.

But anyway, as far as I can tell from my own machine, the _CRS in the
DSDT table never lists the HPET interrupts, and the HPET registration is
always done by hpet_reserve_platform_timers() in arch/x86/kernel/hpet.c.
Try adding logging to hpet_late_init() to find out why it aborts.


Regards,
Clemens