Messages in this thread Patch in this message | | | From | "Rafael J. Wysocki" <> | Subject | [PATCH] ACPI: PM: Fix regression in acpi_device_set_power() | Date | Thu, 01 Aug 2019 01:31:08 +0200 |
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From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Commit f850a48a0799 ("ACPI: PM: Allow transitions to D0 to occur in special cases") overlooked the fact that acpi_power_transition() may change the power.state value for the target device and if that happens, it may confuse acpi_device_set_power() and cause it to omit the _PS0 evaluation which on some systems is necessary to change power states of devices from low-power to D0.
Fix that by saving the current value of power.state for the target device before passing it to acpi_power_transition() and using the saved value in a subsequent check.
Fixes: f850a48a0799 ("ACPI: PM: Allow transitions to D0 to occur in special cases") Reported-by: Kai-Heng Feng <kai.heng.feng@canonical.com> Reported-by: Mario Limonciello <mario.limonciello@dell.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> --- drivers/acpi/device_pm.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
Index: linux-pm/drivers/acpi/device_pm.c =================================================================== --- linux-pm.orig/drivers/acpi/device_pm.c +++ linux-pm/drivers/acpi/device_pm.c @@ -236,13 +236,15 @@ int acpi_device_set_power(struct acpi_de if (device->power.flags.power_resources) result = acpi_power_transition(device, target_state); } else { + int cur_state = device->power.state; + if (device->power.flags.power_resources) { result = acpi_power_transition(device, ACPI_STATE_D0); if (result) goto end; } - if (device->power.state == ACPI_STATE_D0) { + if (cur_state == ACPI_STATE_D0) { int psc; /* Nothing to do here if _PSC is not present. */
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