Merge tag 'acpica-4.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael...

[cascardo/linux.git] / drivers / acpi / Kconfig

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index f15db00..114cf48 100644 (file)
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -80,6 +80,26 @@ 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