42 lines
1.4 KiB
Diff
42 lines
1.4 KiB
Diff
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From a7edc17544709d20f800dc0898096365a3d68613 Mon Sep 17 00:00:00 2001
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From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
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Date: Sun, 2 Jun 2019 16:36:15 +0200
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Subject: [PATCH] acpi/arm64: ignore 5.1 FADTs that are reported as 5.0
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Some Qualcomm Snapdragon based laptops built to run Microsoft Windows
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are clearly ACPI 5.1 based, given that that is the first ACPI revision
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that supports ARM, and introduced the FADT 'arm_boot_flags' field,
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which has a non-zero field on those systems.
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So in these cases, infer from the ARM boot flags that the FADT must be
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5.1 or later, and treat it as 5.1.
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Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
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---
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arch/arm64/kernel/acpi.c | 10 +++++++---
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1 file changed, 7 insertions(+), 3 deletions(-)
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diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
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index 803f0494dd3e3..7722e85fb69c3 100644
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--- a/arch/arm64/kernel/acpi.c
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+++ b/arch/arm64/kernel/acpi.c
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@@ -155,10 +155,14 @@ static int __init acpi_fadt_sanity_check(void)
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*/
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if (table->revision < 5 ||
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(table->revision == 5 && fadt->minor_revision < 1)) {
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- pr_err("Unsupported FADT revision %d.%d, should be 5.1+\n",
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+ pr_err(FW_BUG "Unsupported FADT revision %d.%d, should be 5.1+\n",
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table->revision, fadt->minor_revision);
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- ret = -EINVAL;
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- goto out;
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+
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+ if (!fadt->arm_boot_flags) {
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+ ret = -EINVAL;
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+ goto out;
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+ }
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+ pr_err("FADT has ARM boot flags set, assuming 5.1\n");
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}
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if (!(fadt->flags & ACPI_FADT_HW_REDUCED)) {
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