Author :
jsg
Date :
2020-09-16 11:52:17
Hash :dd1b5e45 Message :disable acpivout brightness control on machines aware of Windows 8
On a HP ProBook 650 G1 acpivout backlight brightness control only works
if we don't claim to be Windows 8. If we don't claim to be Windows 8
_BCL gives 21 levels with increments of 5, otherwise 101 levels (0-100)
and a _BCM that does nothing. This is related to requirements Microsoft
has for Windows 8 and later hardware certification.
Having acpivout not fully attach lets inteldrm handle brightness ioctls.
Brightness control via physical buttons will require a new acpi driver
for the HP flavour of WMI.
Add Windows 10 2004 _OSI value to the list while here.
ok mpi@ kmos@ on an earlier version
tested by kmos@ on 6460b and 6470b ProBooks which had the same problem
feedback and ok kettenis@
jsg