The following commit has been merged into the efi/urgent branch of tip:

Commit-ID: 355845b738e76445c8522802552146d96cb4afa7 Gitweb: https://git.kernel.org/tip/355845b738e76445c8522802552146d96cb4afa7 Author: Lukas Wunner lukas@wunner.de AuthorDate: Thu, 31 Dec 2020 06:10:32 +01:00 Committer: Ard Biesheuvel ardb@kernel.org CommitterDate: Thu, 31 Dec 2020 10:28:53 +01:00

efi/apple-properties: Reinstate support for boolean properties

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 --- drivers/firmware/efi/apple-properties.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/firmware/efi/apple-properties.c b/drivers/firmware/efi/apple-properties.c index 34f53d8..e192648 100644 --- 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_pairs(struct dev_header *dev_header,

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,