Set up an handler for ACPI events and respond to brightness change
requests from the system BIOS.
v2: fix notification when using device-specific command codes
(tested by Pali Rohár <pali.rohar@gmail.com>); cache the encoder
controlling the backlight during the initialization to avoid searching
it every time (suggested by Alex Deucher).
v3: whitespace fixes (Alex Deucher).
Signed-off-by: Luca Tettamanti <kronos.it@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Add a new header that defines the AMD ACPI interface used
for laptops, PowerXpress, and chipset specific functionality
and update the current code to use it.
Todo:
- properly verify the ACPI interfaces
- hook up and handle ACPI notifications
- make PX code more robust
- implement PCIe Gen and width switching using ACPI
v2: fix typo in header
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>