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  • Rafael J. Wysocki's avatar
    ACPI / init: Make it possible to override _REV · 18d78b64
    Rafael J. Wysocki authored
    
    
    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: default avatarDominik Brodowski <linux@dominikbrodowski.net>
    Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
    18d78b64