thinkpad-acpi: rework brightness support
authorHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Sat, 4 Apr 2009 04:25:53 +0000 (04:25 +0000)
committerLen Brown <len.brown@intel.com>
Sat, 4 Apr 2009 07:14:53 +0000 (03:14 -0400)
commit0e501834f8c2ba7de2a56e332d346dcf4ac0b593
tree97aa4223015bbb43ffeced0812b243e42f8ba872
parent74a60c0f828016456fc635feae388ffd12bb3bb9
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>
Documentation/laptops/thinkpad-acpi.txt
drivers/platform/x86/thinkpad_acpi.c