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| author |   Alex Hung <alex.hung@canonical.com> | 2018-07-18 11:46:55 -0700 |
|---|---|---|
| committer |   Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2018-07-20 10:12:41 +0200 |
| commit | 887532ca7ca59fcf0547a79211756791128030a3 (patch) | |
| tree | 2946ce1cc669c3e7ef15b2884a59b1502cfc049a /drivers/acpi | |
| parent | Linux 4.18-rc5 (diff) | |
| download | linux-dev-887532ca7ca59fcf0547a79211756791128030a3.tar.xz linux-dev-887532ca7ca59fcf0547a79211756791128030a3.zip | |
ACPI / OSI: Add OEM _OSI string to enable NVidia HDMI audio
Some ThinkPad systems have a power-saving feature that turns off HDMI
audio device in Windows, but NVidia Linux driver does not support this
feature. As a result, HDMI audio will not work on Linux.
A BIOS workaround is added with an OEM_OSI string
"Linux-Lenovo-NV-HDMI-Audio" to power on NVidia HDMI audio when booting.
The form of the OEM _OSI strings is defined by each OEMs and is
discussed in Documentation/acpi/osi.txt.
Signed-off-by: Alex Hung <alex.hung@canonical.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/acpi')
| -rw-r--r-- | drivers/acpi/osi.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/acpi/osi.c b/drivers/acpi/osi.c index 8a8f43568510..b2a16ed7e81a 100644 --- a/drivers/acpi/osi.c +++ b/drivers/acpi/osi.c @@ -66,6 +66,14 @@ osi_setup_entries[OSI_STRING_ENTRIES_MAX] __initdata = { * be removed if both new and old graphics cards are supported. */ {"Linux-Dell-Video", true}, + /* + * Linux-Lenovo-NV-HDMI-Audio is used by BIOS to power on NVidia's HDMI + * audio device which is turned off for power-saving in Windows OS. + * This power management feature observed on some Lenovo Thinkpad + * systems which will not be able to output audio via HDMI without + * a BIOS workaround. + */ + {"Linux-Lenovo-NV-HDMI-Audio", true}, }; static u32 acpi_osi_handler(acpi_string interface, u32 supported) |