From d0524885b1574ccff0d159a87fe05077d8579ebe Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Wed, 19 Jun 2019 14:18:31 +0200 Subject: [PATCH] acpi/arm64: ignore 5.1 FADTs that are reported as 5.0 [ Upstream commit 2af22f3ec3ca452f1e79b967f634708ff01ced8a ] Some Qualcomm Snapdragon based laptops built to run Microsoft Windows are clearly ACPI 5.1 based, given that that is the first ACPI revision that supports ARM, and introduced the FADT 'arm_boot_flags' field, which has a non-zero field on those systems. So in these cases, infer from the ARM boot flags that the FADT must be 5.1 or later, and treat it as 5.1. Acked-by: Sudeep Holla Tested-by: Lee Jones Reviewed-by: Graeme Gregory Acked-by: Lorenzo Pieralisi Acked-by: Hanjun Guo Signed-off-by: Ard Biesheuvel Signed-off-by: Catalin Marinas Signed-off-by: Sasha Levin --- arch/arm64/kernel/acpi.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c index 252a6d9..1a95d13 100644 --- a/arch/arm64/kernel/acpi.c +++ b/arch/arm64/kernel/acpi.c @@ -157,10 +157,14 @@ static int __init acpi_fadt_sanity_check(void) */ if (table->revision < 5 || (table->revision == 5 && fadt->minor_revision < 1)) { - pr_err("Unsupported FADT revision %d.%d, should be 5.1+\n", + pr_err(FW_BUG "Unsupported FADT revision %d.%d, should be 5.1+\n", table->revision, fadt->minor_revision); - ret = -EINVAL; - goto out; + + if (!fadt->arm_boot_flags) { + ret = -EINVAL; + goto out; + } + pr_err("FADT has ARM boot flags set, assuming 5.1\n"); } if (!(fadt->flags & ACPI_FADT_HW_REDUCED)) { -- 2.7.4