Rafael J. Wysocki wrote:

On Wed, Apr 20, 2022 at 3:44 PM Ville Syrjala ville.syrjala@linux.intel.com wrote:

...

From: Ville Syrjälä ville.syrjala@linux.intel.com

commit d6b88ce2eb9d ("ACPI: processor idle: Allow playing dead in C3 state") was supposedly just trying to enable C3 when the CPU is offlined, but it also mistakenly enabled C3 usage without setting ARB_DIS=1 in normal idle scenarios.

This results in a machine that won't boot past the point when it first enters C3. Restore the correct behaviour (either demote to C1/C2, or use C3 but also set ARB_DIS=1).

I hit this on a Fujitsu Siemens Lifebook S6010 (P3) machine.

Cc: stable@vger.kernel.org Cc: Woody Suwalski wsuwalski@gmail.com Cc: Mario Limonciello mario.limonciello@amd.com Cc: Richard Gong richard.gong@amd.com Cc: Rafael J. Wysocki rafael.j.wysocki@intel.com Fixes: d6b88ce2eb9d ("ACPI: processor idle: Allow playing dead in C3 state") Signed-off-by: Ville Syrjälä ville.syrjala@linux.intel.com

---

drivers/acpi/processor_idle.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index 4556c86c3465..54f0a1915025 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -793,10 +793,10 @@ static int acpi_processor_setup_cstates(struct acpi_processor *pr)

             state->flags = 0;
             if (cx->type == ACPI_STATE_C1 || cx->type == ACPI_STATE_C2 ||

•               cx->type == ACPI_STATE_C3) {
  

•               cx->type == ACPI_STATE_C3)
                     state->enter_dead = acpi_idle_play_dead;
  

•           if (cx->type == ACPI_STATE_C1 || cx->type == ACPI_STATE_C2)
                     drv->safe_state_index = count;
  

•           }
             /*
              * Halt-induced C1 is not good for ->enter_s2idle, because it
              * re-enables interrupts on exit.  Moreover, C1 is generally not
  

--

Good catch, but I would prefer doing the below which should be equivalent (modulo GMail-induced white space breakage):

---

drivers/acpi/processor_idle.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

Index: linux-pm/drivers/acpi/processor_idle.c

--- linux-pm.orig/drivers/acpi/processor_idle.c +++ linux-pm/drivers/acpi/processor_idle.c @@ -795,7 +795,8 @@ static int acpi_processor_setup_cstates( if (cx->type == ACPI_STATE_C1 || cx->type == ACPI_STATE_C2 || cx->type == ACPI_STATE_C3) { state->enter_dead = acpi_idle_play_dead;

•        drv->safe_state_index = count;
  

•        if (cx->type != ACPI_STATE_C3)
  

•            drv->safe_state_index = count;
      }
      /*
       * Halt-induced C1 is not good for ->enter_s2idle, because it
  

I have tested both solutions from Ville and Rafael, and both work OK on T40. Clearly, since Ville has duped the issue on a non-T40 machine, the processor_power_dmi_table[] solution is incorrect.

Rafael's solution seems simpler - so I also like it more :-)

Thanks, Woody