diff options
author | Mario Limonciello <mario.limonciello@amd.com> | 2023-08-18 14:40:07 -0500 |
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committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2023-08-21 20:28:20 +0200 |
commit | 1c2a66d47de36608551d73562d01bb4afcf1d61a (patch) | |
tree | 0cd888ff33c59fef4d7af4473475f28317b6524b /drivers/acpi | |
parent | 41233988112f0f5fb015172a8db68a3c052aedda (diff) |
ACPI: x86: s2idle: Add a function to get LPS0 constraint for a device
Other parts of the kernel may use LPS0 constraints information to make
decisions on what power state to put a device into.
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
[ rjw: Rewrite kerneldoc, rearrange if () statement, edit subject and
changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/acpi')
-rw-r--r-- | drivers/acpi/x86/s2idle.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/drivers/acpi/x86/s2idle.c b/drivers/acpi/x86/s2idle.c index 1aa3cd5677bd..08f7c6708206 100644 --- a/drivers/acpi/x86/s2idle.c +++ b/drivers/acpi/x86/s2idle.c @@ -299,6 +299,30 @@ free_acpi_buffer: ACPI_FREE(out_obj); } +/** + * acpi_get_lps0_constraint - Get the LPS0 constraint for a device. + * @adev: Device to get the constraint for. + * + * The LPS0 constraint is the shallowest (minimum) power state in which the + * device can be so as to allow the platform as a whole to achieve additional + * energy conservation by utilizing a system-wide low-power state. + * + * Returns: + * - ACPI power state value of the constraint for @adev on success. + * - Otherwise, ACPI_STATE_UNKNOWN. + */ +int acpi_get_lps0_constraint(struct acpi_device *adev) +{ + struct lpi_constraints *entry; + + for_each_lpi_constraint(entry) { + if (adev->handle == entry->handle) + return entry->min_dstate; + } + + return ACPI_STATE_UNKNOWN; +} + static void lpi_check_constraints(void) { struct lpi_constraints *entry; |