From: Lukas Wunner lukas@wunner.de
commit 355845b738e76445c8522802552146d96cb4afa7 upstream.
Since commit 4466bf82821b ("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".
Commit 6e98503dba64 ("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.
Commit 4466bf82821b erroneously 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: 4466bf82821b ("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/be958bda75331a011d53c696d1deec8dccd06fd2.160938854... Signed-off-by: Ard Biesheuvel ardb@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/firmware/efi/apple-properties.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-)
--- a/drivers/firmware/efi/apple-properties.c +++ b/drivers/firmware/efi/apple-properties.c @@ -3,8 +3,9 @@ * apple-properties.c - EFI device properties on Macs * Copyright (C) 2016 Lukas Wunner lukas@wunner.de * - * Note, all properties are considered as u8 arrays. - * To get a value of any of them the caller must use device_property_read_u8_array(). + * Properties are stored either as: + * u8 arrays which can be retrieved with device_property_read_u8_array() or + * booleans which can be queried with device_property_present(). */
#define pr_fmt(fmt) "apple-properties: " fmt @@ -88,8 +89,12 @@ static void __init unmarshal_key_value_p
entry_data = ptr + key_len + sizeof(val_len); entry_len = val_len - sizeof(val_len); - entry[i] = PROPERTY_ENTRY_U8_ARRAY_LEN(key, entry_data, - entry_len); + if (entry_len) + entry[i] = PROPERTY_ENTRY_U8_ARRAY_LEN(key, entry_data, + entry_len); + else + entry[i] = PROPERTY_ENTRY_BOOL(key); + if (dump_properties) { dev_info(dev, "property: %s\n", key); print_hex_dump(KERN_INFO, pr_fmt(), DUMP_PREFIX_OFFSET,