thinkpad-acpi: rework brightness support
Refactor and redesign the brightness control backend...
In order to fix bugzilla #11750...
Add a new brightness control mode: support direct NVRAM checkpointing
of the backlight level (i.e. store directly to NVRAM without the need
for UCMS calls), and use that together with the EC-based control.
Disallow UCMS+EC, thus avoiding races with the SMM firmware.
Switch the models that define HBRV (EC Brightness Value) in the DSDT
to the new mode. These are: T40-T43, R50-R52, R50e, R51e, X31-X41.
Change the default for all other IBM ThinkPads to UCMS-only. The
Lenovo models already default to UCMS-only.
Reported-by: Alexey Fisher <bug-track@fisher-privat.net>
Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Len Brown <len.brown@intel.com>
2 files changed