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commit355845b738upstream. Since commit4466bf8282("efi/apple-properties: use PROPERTY_ENTRY_U8_ARRAY_LEN"), my MacBook Pro issues a -ENODATA error when trying to assign EFI properties to the discrete GPU: pci 0000:01:00.0: assigning 56 device properties pci 0000:01:00.0: error -61 assigning properties That's because some of the properties have no value. They're booleans whose presence can be checked by drivers, e.g. "use-backlight-blanking". Commit6e98503dba("efi/apple-properties: Remove redundant attribute initialization from unmarshal_key_value_pairs()") employed a trick to store such booleans as u8 arrays (which is the data type used for all other EFI properties on Macs): It cleared the property_entry's "is_array" flag, thereby denoting that the value is stored inline in the property_entry. Commit4466bf8282erroneously removed that trick. It was probably a little fragile to begin with. Reinstate support for boolean properties by explicitly invoking the PROPERTY_ENTRY_BOOL() initializer for properties with zero-length value. Fixes:4466bf8282("efi/apple-properties: use PROPERTY_ENTRY_U8_ARRAY_LEN") Cc: <stable@vger.kernel.org> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Lukas Wunner <lukas@wunner.de> Link: https://lore.kernel.org/r/be958bda75331a011d53c696d1deec8dccd06fd2.1609388549.git.lukas@wunner.de Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.