Commit 55087c57 authored Jan 31, 2020 by Hans de Goede Committed by Ard Biesheuvel Feb 22, 2020

efi/bgrt: Accept BGRT tables with a version of 0



Some (somewhat older) laptops have a correct BGRT table, except that the
version field is 0 instead of 1.

This has been seen on several Ivy Bridge based Lenovo models.

For now the spec. only defines version 1, so it is reasonably safe to
assume that tables with a version of 0 really are version 1 too,
which is what this commit does so that the BGRT table will be accepted
by the kernel on laptop models with this issue.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20200131130623.33875-1-hdegoede@redhat.com


Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

parent f32ea1cd

drivers/firmware/efi/efi-bgrt.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -42,7 +42,12 @@ void __init efi_bgrt_init(struct acpi_table_header *table)
		return;
		}
		bgrt = (struct acpi_table_bgrt *)table;
		if (bgrt->version != 1) {
		/*
		* Only version 1 is defined but some older laptops (seen on Lenovo
		* Ivy Bridge models) have a correct version 1 BGRT table with the
		* version set to 0, so we accept version 0 and 1.
		*/
		if (bgrt->version > 1) {
		pr_notice("Ignoring BGRT: invalid version %u (expected 1)\n",
		bgrt->version);
		goto out;

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