lkml.org 
[lkml]   [2021]   [Mar]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v2 2/2] ACPI: power: Turn off unused power resources unconditionally
Date
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

According to the ACPI specification (section 7.2.2 in ACPI 6.4), the
OS may evaluate the _OFF method of a power resource that is "off"
already [1], and in particular that can be done in the case of unused
power resources.

Accordingly, modify acpi_turn_off_unused_power_resources() to
evaluate the _OFF method for each of the unused power resources
unconditionally which may help to work around BIOS issues where the
return value of _STA for a power resource does not reflect the
actual state of the power resource [2].

Link: https://uefi.org/specs/ACPI/6.4/07_Power_and_Performance_Mgmt/declaring-a-power-resource-object.html#off # [1]
Link: https://lore.kernel.org/lkml/20210314000439.3138941-1-luzmaximilian@gmail.com/ # [2]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

New patch in v2.

---
drivers/acpi/power.c | 11 +----------
1 file changed, 1 insertion(+), 10 deletions(-)

Index: linux-pm/drivers/acpi/power.c
===================================================================
--- linux-pm.orig/drivers/acpi/power.c
+++ linux-pm/drivers/acpi/power.c
@@ -1005,18 +1005,9 @@ void acpi_turn_off_unused_power_resource
mutex_lock(&power_resource_list_lock);

list_for_each_entry_reverse(resource, &acpi_power_resource_list, list_node) {
- int result, state;
-
mutex_lock(&resource->resource_lock);

- result = acpi_power_get_state(resource->device.handle, &state);
- if (result) {
- mutex_unlock(&resource->resource_lock);
- continue;
- }
-
- if (state == ACPI_POWER_RESOURCE_STATE_ON
- && !resource->ref_count) {
+ if (!resource->ref_count) {
dev_info(&resource->device.dev, "Turning OFF\n");
__acpi_power_off(resource);
}


\
 
 \ /
  Last update: 2021-03-18 19:30    [W:0.031 / U:0.140 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site