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| author | Hans de Goede <hdegoede@redhat.com> | 2017-12-23 21:41:47 +0300 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2017-12-28 14:45:07 +0300 |
| commit | 5928c281524fe451114e04f1dfa11246a37e859f (patch) | |
| tree | c48be48727499c51cb4ede3ae85ab200c8a2d9b6 /lib/crc16.c | |
| parent | 464e1d5f23cca236b930ef068c328a64cab78fb1 (diff) | |
| download | linux-5928c281524fe451114e04f1dfa11246a37e859f.tar.xz | |
ACPI / video: Default lcd_only to true on Win8-ready and newer machines
We're seeing a lot of bogus backlight interfaces on newer machines without
a LCD such as desktops, servers and HDMI sticks. This causes userspace to
show a non-functional brightness slider in e.g. the GNOME3 system menu,
which is undesirable. And, in general, we should simply just not register
a non functional backlight interface.
Checking the LCD flag causes the bogus acpi_video backlight interfaces to
go away (on the machines this was tested on).
This change sets the lcd_only option by default on any machines which
are Win8-ready, to fix this.
This is not entirely without a risk of regressions, but video_detect.c
already prefers native-backlight interfaces over the acpi_video one
on Win8-ready machines, calling acpi_video_unregister_backlight() as soon
as a native interface shows up. This is done because the ACPI backlight
interface often is broken on Win8-ready machines, because win8 does not
seem to actually use it.
So in practice we already end up not registering the ACPI backlight
interface on (most) Win8-ready machines with a LCD panel, thus this
change does not change anything for (most) machines with a LCD panel
and on machines without a LCD panel we actually don't want to register
any backlight interfaces.
This has been tested on the following machines and fixes a bogus backlight
interface showing up there:
- Desktop with an Asrock B150M Pro4S/D3 m.b. using i5-6500 builtin gfx
- Intel Compute Stick STK1AW32SC
- Meegopad T08 HDMI stick
Bogus backlight interfaces have also been reported on:
- Desktop with Asus H87I-Plus m.b.
- Desktop with ASRock B75M-ITX m.b.
- Desktop with Gigabyte Z87-D3HP m.b.
- Dell PowerEdge T20 desktop
Link: https://bugzilla.redhat.com/show_bug.cgi?id=1097436
Link: https://bugzilla.redhat.com/show_bug.cgi?id=1133327
Link: https://bugzilla.redhat.com/show_bug.cgi?id=1133329
Link: https://bugzilla.redhat.com/show_bug.cgi?id=1133646
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'lib/crc16.c')
0 files changed, 0 insertions, 0 deletions