On Tue, Dec 30, 2025 at 8:50 PM Milky <[email protected]> wrote:
> (Re-CC'ing the ML because I forgot by accident. Hopefully the quoted
> sections provide sufficient context)
>
> On Tuesday, December 30th, 2025 at 10:44 AM, Jason Andryuk 
> <[email protected]> wrote:

> As suggested, I added the debug parameters to the dom0 kernel. Before or
> after `modprobe xen-acpi-processor dyndbg==pmf`, there is no useful
> debug information that I could find, apart from the
> `xen_acpi_processor:get_max_acpi_id` message as seen below.
>
> ```
> # sudo dmesg | grep xen.acpi
> [    2.282851] Kernel command line: placeholder 
> root=/dev/mapper/qubes_dom0-root ro rd.luks.uuid=<...> 
> rd.lvm.lv=qubes_dom0/root rd.lvm.lv=qubes_dom0/swap 
> plymouth.ignore-serial-consoles 6.6.77-1.qubes.fc37.x86_64 x86_64 rhgb 
> loglevel=9 "dyndbg=module xen_acpi_processor +p" 
> "xen_acpi_processor.dyndbg=func * +p" rd.qubes.hide_all_usb
> [    5.224092] xen_acpi_processor: Max ACPI ID: 6

You successfully turned on dyndbg to get that output, but there is no
further output.  This makes me think something else is wrong and
xen-acpi-processor doesn't upload anything.

The call here 
https://elixir.bootlin.com/linux/v6.18.2/source/drivers/xen/xen-acpi-processor.c#L557
to
https://elixir.bootlin.com/linux/v6.18.2/source/drivers/acpi/processor_perflib.c#L421
goes into some acpi code.  Maybe there are other messages in dmesg
around the same time?  Maybe you'd have to turn on more debugging to
get them.

> # sudo lsmod | grep xen_acpi
> <no output>
>
> # sudo modprobe xen-acpi-processor dyndbg==pmf
> modprobe: ERROR: could not insert 'xen_acpi_processor': No such device
> ```

> > Maybe also with Xen's command line try cpufreq=xen:no-hwp to disable
> > HWP and see if the regular ACPI cpufreq driver works better.
> >
> > I'm thinking it's something where xen-acpi-processor didn't upload
> > ACPI CPU data, which means cpufreq isn't running. That may also be
> > why you see that bogus CPU frequency.
>
> After booting with `xen:no-hwp`, I wasn't sure how to check if the
> regular ACPI cpufreq driver is operational. Is `xenpm` still the
> correct way to query for CPU info? I've tried the following:
>
> ```
> # sudo xl dmesg | grep -i hwp
> (XEN) Command line: placeholder cpufreq=xen:no-hwp,verbose loglvl=all 
> dom0_mem=min:1024M dom0_mem=max:4096M ucode=scan smt=off 
> gnttab_max_frames=2048 gnttab_max_maptrack_frames=4096 no-real-mode edd=off
> (XEN) HWP: 1 notify: 1 act-window: 1 energy-perf: 1 pkg-level: 0 peci: 0
> (XEN) HWP: Hardware Duty Cycling (HDC) supported, enabled
> (XEN) HWP: HW_FEEDBACK not supported

no-hwp failed to disable HWP.  But if there is no ACPI CPU data, it
wouldn't work either.

You could de-compile the ACPI tables and see if they have CPU info.
Something like:
mkdir acpi-tables
cd acpi-tables
cp /sys/firmware/acpi/tables/* .
iasl -d *
grep -r -e _PCT -e _PPC -e _PSS *.dsl

That could help confirm the tables are missing.

Regards,
Jason

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