]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
UBUNTU: SAUCE: (no-up) ACPI: Disable Windows 8 compatibility for some Lenovo ThinkPads
authorSeth Forshee <seth.forshee@canonical.com>
Fri, 20 Sep 2013 18:03:41 +0000 (13:03 -0500)
committerAndrea Righi <andrea.righi@canonical.com>
Thu, 9 Mar 2023 14:57:10 +0000 (15:57 +0100)
commitbd3f2f91cde5d68dfb071e7c47987d966c3a771e
treebbdc17b8d5407af6822fde9ccb42a8a55e89cf05
parent88b73c1b988b4ac8243b923a6c21cc170a32a4ce
UBUNTU: SAUCE: (no-up) ACPI: Disable Windows 8 compatibility for some Lenovo ThinkPads

The AML implementation for brightness control on several ThinkPads
contains a workaround to meet a Windows 8 requirement of 101 brightness
levels [1]. The implementation is flawed, as only 16 of the brighness
values reported by _BCL affect a change in brightness. _BCM silently
discards the rest of the values. Disabling Windows 8 compatibility on
these machines reverts them to the old behavior, making _BCL only report
the 16 brightness levels which actually work. Add a quirk to do this
along with a dmi callback to disable Win8 compatibility.

[1] http://msdn.microsoft.com/en-us/library/windows/hardware/jj128256.aspx

BugLink: http://bugs.launchpad.net/bugs/1183856
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
drivers/acpi/osi.c