Re: Cpufreq drivers not working on T480S

[Milky <milky_way_303030@xxxxxxxxx>]

On Thursday, January 15th, 2026 at 10:51 AM, Jan Beulich <jbeulich@xxxxxxxx> 
wrote:

> 
> 
> On 15.01.2026 00:42, Milky wrote:
> 
> > On Wednesday, January 14th, 2026 at 11:12 AM, Jan Beulich jbeulich@xxxxxxxx 
> > wrote:
> > 
> > > On 14.01.2026 11:58, Milky wrote:
> > > 
> > > > Just wanted to update this thread to say that now another T480 user 
> > > > (the T480 is a very similar model to my T480S) using the release builds 
> > > > of libreboot (as of 26.01 RC1) also has the entries missing from the 
> > > > ACPI tables. That discussion was here 
> > > > https://codeberg.org/libreboot/lbmk/issues/394. So this confirms that 
> > > > I'm running a standard libreboot, rather than a bad build.
> > > > 
> > > > Do you think there is any way to avoid the underclocking issue with Xen 
> > > > on such devices/firmware?
> > > 
> > > In principle there is, but in the absence of ACPI data that means holding 
> > > model-
> > > specific data in Xen. Which iirc is what the intel-pstate driver in Linux 
> > > does
> > > (using ACPI info nowadays only as "auxiliary" data). But I may be wrong 
> > > there,
> > > as it has been a long time since I last looked at that driver.
> > 
> > In that case, would you say this is settled now? Would it make sense to 
> > report back to the QubesOS community that librebooted T480/S will run 
> > underclocked, due to the missing data in ACPI tables and lack of native 
> > support in Xen? This information is important, as the device is only barely 
> > usable.
> 
> 
> What to suggest to the Qubes community needs to be discussed there, I think.
> 
> Jan

I was just hoping to confirm with you that my understanding is correct, in 
order not to pass the wrong information. In fact I intend to report this to the 
libreboot/coreboot community too, in case there is a way to include the missing 
data in ACPI tables. But first I wanted to make sure that from the Xen 
perspective, we got to the bottom of it. 

Thanks for your time.