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authorVille Syrjälä <ville.syrjala@linux.intel.com>2022-04-21 16:36:34 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2022-04-21 19:55:41 +0200
commitfc45e55ebc58dbf622cb89ddbf797589c7a5510b (patch)
treee0437ec315350966bf2bf6ae3c90c256b6664067 /drivers/acpi
parentb2d229d4ddb17db541098b83524d901257e93845 (diff)
ACPI: processor: idle: Avoid falling back to C3 type C-states
The "safe state" index is used by acpi_idle_enter_bm() to avoid entering a C-state that may require bus mastering to be disabled on entry in the cases when this is not going to happen. For this reason, it should not be set to point to C3 type of C-states, because they may require bus mastering to be disabled on entry in principle. This was broken by commit d6b88ce2eb9d ("ACPI: processor idle: Allow playing dead in C3 state") which inadvertently allowed the "safe state" index to point to C3 type of C-states. 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. Fixes: d6b88ce2eb9d ("ACPI: processor idle: Allow playing dead in C3 state") Cc: 5.16+ <stable@vger.kernel.org> # 5.16+ Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Tested-by: Woody Suwalski <wsuwalski@gmail.com> [ rjw: Subject and changelog adjustments ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/acpi')
-rw-r--r--drivers/acpi/processor_idle.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 4556c86c3465..5f296e099bce 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -795,7 +795,8 @@ static int acpi_processor_setup_cstates(struct acpi_processor *pr)
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