Re: Pressing the power button causes the device to freeze completely

[Rafael J. Wysocki]

On Sun, Apr 26, 2026 at 4:50 PM Rafael J. Wysocki <rafael@xxxxxxxxxx> wrote:
>
> On Friday, April 24, 2026 11:18:02 PM CEST Evgeny Sagatov wrote:
> > dmesg | grep "Fast frequency"
> > Nothing was displayed.
> >
> > The PC froze when I pressed the power button. Nothing in the log.
> >
> > I applied this patch after deleting all the previous ones. Is this correct?
>
> Yes, it is.
>
> > I received this message when applying a patch. Perhaps we have
> > different versions of the source code? I'm using 7.0.0.
> > patching file drivers/acpi/acpica/evevent.c
> > patching file drivers/cpufreq/acpi-cpufreq.c
> > Hunk #1 succeeded at 895 (offset -17 lines).
> > patching file drivers/cpufreq/cpufreq.c
>
> That should be fine.
>
> We've switched over schedutil to a different code path and the problem is
> still there, so it appears to be related to hardware accesses.
>
> To test this, please apply the patch below (which is a replacement for the
> previous patch) and collect the output of
>
> $ dmesg | grep ""

This should have been

$ dmesg | grep "frequency scaling"

(pressed "send" too early, sorry about that) but sending a complete
dmesg log (which would be produced by grepping for an empty string)
would work either.

> after a fresh boot.  Please let me know what's there.
>
> Also, the "Fast frequency switching enabled" messages should be back.
>
> Then, check what happens when the power button is pressed (if the system
> doesn't lock up, a message should be printed to the kernel log every time
> the power button is pressed).
>
> With this patch applied, schedutil will not access hardware in the fast
> frequency switching path, so the frequency scaling will not actually work
> (this is roughly equivalent to running the "performance" or "powersave"
> governor all the time).
>
> ---
>  drivers/acpi/acpica/evevent.c  |    5 +++++
>  drivers/cpufreq/acpi-cpufreq.c |    6 ++++--
>  drivers/cpufreq/cpufreq.c      |    1 +
>  3 files changed, 10 insertions(+), 2 deletions(-)
>
> --- a/drivers/acpi/acpica/evevent.c
> +++ b/drivers/acpi/acpica/evevent.c
> @@ -243,6 +243,11 @@ static u32 acpi_ev_fixed_event_dispatch(
>         (void)acpi_write_bit_register(acpi_gbl_fixed_event_info[event].
>                                       status_register_id, ACPI_CLEAR_STATUS);
>
> +       if (event == ACPI_EVENT_POWER_BUTTON) {
> +               pr_info("ACPI power button event\n");
> +               return (ACPI_INTERRUPT_HANDLED);
> +       }
> +
>         /*
>          * Make sure that a handler exists. If not, report an error
>          * and disable the event to prevent further interrupts.
> --- a/drivers/cpufreq/acpi-cpufreq.c
> +++ b/drivers/cpufreq/acpi-cpufreq.c
> @@ -479,8 +479,8 @@ static unsigned int acpi_cpufreq_fast_sw
>                         return next_freq;
>         }
>
> -       data->cpu_freq_write(&perf->control_register,
> -                            perf->states[next_perf_state].control);
> +       /*data->cpu_freq_write(&perf->control_register,
> +                            perf->states[next_perf_state].control);*/
>         perf->state = next_perf_state;
>         return next_freq;
>  }
> @@ -887,9 +887,11 @@ static int acpi_cpufreq_cpu_init(struct
>                  * unknown and not detectable via IO ports.
>                  */
>                 policy->cur = acpi_cpufreq_guess_freq(data, policy->cpu);
> +               pr_info("CPU%u: Using I/O space for frequency scaling\n", cpu);
>                 break;
>         case ACPI_ADR_SPACE_FIXED_HARDWARE:
>                 acpi_cpufreq_driver.get = get_cur_freq_on_cpu;
> +               pr_info("CPU%u: Using FFH for frequency scaling\n", cpu);
>                 break;
>         default:
>                 break;
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -473,6 +473,7 @@ void cpufreq_enable_fast_switch(struct c
>         if (cpufreq_fast_switch_count >= 0) {
>                 cpufreq_fast_switch_count++;
>                 policy->fast_switch_enabled = true;
> +               pr_info("CPU%u: Fast frequency switching enabled\n", policy->cpu);
>         } else {
>                 pr_warn("CPU%u: Fast frequency switching not enabled\n",
>                         policy->cpu);
>
>
>
>