From e2174b0c24caca170ca61eda2ae49c9561ff8896 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Mon, 14 Nov 2016 20:56:17 +0100 Subject: Revert "ACPICA: FADT support cleanup" Pavel Machek reports that commit 6ea8c546f365 (ACPICA: FADT support cleanup) breaks thermal management on his Thinkpad X60 and T40p, so revert it. Link: https://bugzilla.kernel.org/show_bug.cgi?id=187311 Fixes: 6ea8c546f365 (ACPICA: FADT support cleanup) Reported-by: Pavel Machek Signed-off-by: Rafael J. Wysocki --- drivers/acpi/acpica/tbfadt.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) (limited to 'drivers/acpi/acpica/tbfadt.c') diff --git a/drivers/acpi/acpica/tbfadt.c b/drivers/acpi/acpica/tbfadt.c index 046c4d0394ee..5fb838e592dc 100644 --- a/drivers/acpi/acpica/tbfadt.c +++ b/drivers/acpi/acpica/tbfadt.c @@ -480,19 +480,17 @@ static void acpi_tb_convert_fadt(void) u32 i; /* - * For ACPI 1.0 FADTs (revision 1), ensure that reserved fields which + * For ACPI 1.0 FADTs (revision 1 or 2), ensure that reserved fields which * should be zero are indeed zero. This will workaround BIOSs that * inadvertently place values in these fields. * * The ACPI 1.0 reserved fields that will be zeroed are the bytes located * at offset 45, 55, 95, and the word located at offset 109, 110. * - * Note: The FADT revision value is unreliable because of BIOS errors. - * The table length is instead used as the final word on the version. - * - * Note: FADT revision 3 is the ACPI 2.0 version of the FADT. + * Note: The FADT revision value is unreliable. Only the length can be + * trusted. */ - if (acpi_gbl_FADT.header.length <= ACPI_FADT_V3_SIZE) { + if (acpi_gbl_FADT.header.length <= ACPI_FADT_V2_SIZE) { acpi_gbl_FADT.preferred_profile = 0; acpi_gbl_FADT.pstate_control = 0; acpi_gbl_FADT.cst_control = 0; -- cgit v1.2.3-59-g8ed1b