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| author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2015-07-03 01:06:00 +0200 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2015-07-03 01:06:00 +0200 |
| commit | 18d78b64fddc11eb336f01e46ad3303a3f55d039 (patch) | |
| tree | 806559410131313aa86fa78510e34f1592cbb4ad /drivers/acpi/Kconfig | |
| parent | ce55d01e9b4daee5040777d023d52e6b42d3ad8f (diff) | |
| download | op-kernel-dev-18d78b64fddc11eb336f01e46ad3303a3f55d039.zip op-kernel-dev-18d78b64fddc11eb336f01e46ad3303a3f55d039.tar.gz | |
ACPI / init: Make it possible to override _REV
The platform firmware on some systems expects Linux to return "5" as
the supported ACPI revision which makes it expose system configuration
information in a special way.
For example, based on what ACPI exports as the supported revision,
Dell XPS 13 (2015) configures its audio device to either work in HDA
mode or in I2S mode, where the former is supposed to be used on Linux
until the latter is fully supported (in the kernel as well as in user
space).
Since ACPI 6 mandates that _REV should return "2" if ACPI 2 or later
is supported by the OS, a subsequent change will make that happen, so
make it possible to override that on systems where "5" is expected to
be returned for Linux to work correctly one them (such as the Dell
machine mentioned above).
Original-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/acpi/Kconfig')
| -rw-r--r-- | drivers/acpi/Kconfig | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig index ab2cbb5..2b652f1 100644 --- a/drivers/acpi/Kconfig +++ b/drivers/acpi/Kconfig @@ -77,6 +77,26 @@ config ACPI_PROCFS_POWER Say N to delete power /proc/acpi/ directories that have moved to /sys/ +config ACPI_REV_OVERRIDE_POSSIBLE + bool "Allow supported ACPI revision to be overriden" + depends on X86 + default y + help + The platform firmware on some systems expects Linux to return "5" as + the supported ACPI revision which makes it expose system configuration + information in a special way. + + For example, based on what ACPI exports as the supported revision, + Dell XPS 13 (2015) configures its audio device to either work in HDA + mode or in I2S mode, where the former is supposed to be used on Linux + until the latter is fully supported (in the kernel as well as in user + space). + + This option enables a DMI-based quirk for the above Dell machine (so + that HDA audio is exposed by the platform firmware to the kernel) and + makes it possible to force the kernel to return "5" as the supported + ACPI revision via the "acpi_rev_override" command line switch. + config ACPI_EC_DEBUGFS tristate "EC read/write access through /sys/kernel/debug/ec" default n |
