| Message ID | 1531939615-17301-1-git-send-email-alex.hung@canonical.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Delegated to: | Rafael Wysocki |
| Headers | show |
On Wednesday, July 18, 2018 8:46:55 PM CEST Alex Hung wrote: > 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> > --- > drivers/acpi/osi.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/acpi/osi.c b/drivers/acpi/osi.c > index 8a8f435..b2a16ed 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) > Applied, thanks! -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/acpi/osi.c b/drivers/acpi/osi.c index 8a8f435..b2a16ed 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)
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> --- drivers/acpi/osi.c | 8 ++++++++ 1 file changed, 8 insertions(+)