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

["Rafael J. Wysocki" <rafael@kernel.org>]

On Wednesday, April 22, 2026 4:48:41 PM CEST Evgeny Sagatov wrote:
> > There are two cpufreq governors to choose from.  Have you decided to compile out the other ones on purpose?
> 
> Powersave is compiled into the stock Debian kernel as a module, so it
> does not appear in this list.
> 
> I changed governor to powersave and pressed the power button. The PC
> shut down normally.

Interesting.

Can you please also check what happens if you change the cpufreq governor
to "performance" (on all CPUs) before pressing the power button?

The difference is that with the "performance" governor the CPUs will be
running at the highest frequency.

> ср, 22 апр. 2026 г. в 17:04, Rafael J. Wysocki <rafael@kernel.org>:
> >
> > On Wed, Apr 22, 2026 at 3:34 PM Evgeny Sagatov <evgeny.sagatov@gmail.com> wrote:
> > >
> > > # grep -r . /sys/devices/system/cpu/cpufreq/
> > > /sys/devices/system/cpu/cpufreq/schedutil/rate_limit_us:240
> > > /sys/devices/system/cpu/cpufreq/policy2/scaling_min_freq:2000000
> > > /sys/devices/system/cpu/cpufreq/policy2/scaling_available_governors:performance
> > > schedutil
> >
> > There are two cpufreq governors to choose from.  Have you decided to
> > compile out the other ones on purpose?
> >
> > It might be useful to compile the powersave governor in and try to
> > switch over to it (on all CPUs) before pressing the power button
> > (without any patches applied).
> >
> > > /sys/devices/system/cpu/cpufreq/policy2/freqdomain_cpus:2
> > > /sys/devices/system/cpu/cpufreq/policy2/scaling_governor:schedutil
> > > /sys/devices/system/cpu/cpufreq/policy2/cpuinfo_max_freq:2834000
> > > /sys/devices/system/cpu/cpufreq/policy2/scaling_available_frequencies:2834000
> > > 2000000
> >
> > The frequency scaling on this CPU is quite limited (only 2 states to
> > choose from).
> >
> > > /sys/devices/system/cpu/cpufreq/policy2/related_cpus:2
> > > /sys/devices/system/cpu/cpufreq/policy2/scaling_cur_freq:2000088
> >
> > Interestingly, this number doesn't match the available choices (maybe
> > due to a rounding error or similar).
> >
> > > /sys/devices/system/cpu/cpufreq/policy2/scaling_setspeed:<unsupported>
> > > grep: /sys/devices/system/cpu/cpufreq/policy2/stats/reset: Access denied
> > > /sys/devices/system/cpu/cpufreq/policy2/stats/trans_table:   From  :    To
> > > /sys/devices/system/cpu/cpufreq/policy2/stats/trans_table:         :
> > > 2834000   2000000
> > > /sys/devices/system/cpu/cpufreq/policy2/stats/trans_table:  2834000:
> > >       0       762
> > > /sys/devices/system/cpu/cpufreq/policy2/stats/trans_table:  2000000:
> > >     761         0
> > > /sys/devices/system/cpu/cpufreq/policy2/stats/total_trans:1523
> > > /sys/devices/system/cpu/cpufreq/policy2/stats/time_in_state:2834000 6606
> > > /sys/devices/system/cpu/cpufreq/policy2/stats/time_in_state:2000000 248733
> > > /sys/devices/system/cpu/cpufreq/policy2/affected_cpus:2
> > > /sys/devices/system/cpu/cpufreq/policy2/scaling_max_freq:2834000
> > > /sys/devices/system/cpu/cpufreq/policy2/cpuinfo_transition_latency:160000
> > > /sys/devices/system/cpu/cpufreq/policy2/scaling_driver:acpi-cpufreq
> > > /sys/devices/system/cpu/cpufreq/policy2/cpuinfo_min_freq:2000000
> > > /sys/devices/system/cpu/cpufreq/policy2/bios_limit:2834000
> >
> > The fact that acpi-cpufreq is the scaling driver may be related to the
> > power button issue in principle.
> >
> > I'm still going to send you another debug patch for the button driver though.

So the patch is appended.  It causes a message to be printed into the kernel
log every time the power button is pressed if all goes well, but the system
will not shut down (it is also not expected to hang).

Please see if that happens with the patch applied (it is a replacement for the
previous debug patch).  In principle it should work without changing the
cpufreq governor.

---
 drivers/acpi/button.c |   10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

--- a/drivers/acpi/button.c
+++ b/drivers/acpi/button.c
@@ -473,14 +473,12 @@ static void acpi_button_notify(acpi_hand
 					event, ++button->pushed);
 }
 
-static void acpi_button_notify_run(void *data)
-{
-	acpi_button_notify(NULL, ACPI_BUTTON_NOTIFY_STATUS, data);
-}
-
 static u32 acpi_button_event(void *data)
 {
-	acpi_os_execute(OSL_NOTIFY_HANDLER, acpi_button_notify_run, data);
+	struct acpi_button *button = data;
+
+	dev_info(button->dev, "ACPI button event\n");
+
 	return ACPI_INTERRUPT_HANDLED;
 }