]> git.proxmox.com Git - mirror_ubuntu-hirsute-kernel.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>
Mon, 15 Feb 2021 07:25:29 +0000 (08:25 +0100)
commitfb6e0719daffd2ff90111d6e31685995a1b906c2
tree8d4627d7f299ee2fb605d43a1976d80bd0ec4b14
parent467af5792f1daf8d2e41147d80acf058874b7f14
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