Merge tag 'acpi-4.9-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull ACPI fixes from Rafael Wysocki:
 "They fix an ACPI thermal management regression introduced by a recent
  FADT handling cleanup, an ACPI tools build issue introduced by a
  recent ACPICA commit and a PCC mailbox initialization bug causing
  lockdep to complain loudly.

  Specifics:

   - Revert a recent ACPICA cleanup that attempted to get rid of all
     FADT version 2 legacy, but broke ACPI thermal management on at
     least one system (Rafael Wysocki).

   - Fix cross-compiled builds of ACPI tools that stopped working after
     a recent cleanup related to the handling of header files in ACPICA
     (Lv Zheng).

   - Fix a locking issue in the PCC channel initialization code that
     invokes devm_request_irq() under a spinlock (among other things)
     and causes lockdep to complain (Hoan Tran)"

* tag 'acpi-4.9-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  tools/power/acpi: Remove direct kernel source include reference
  mailbox: PCC: Fix lockdep warning when request PCC channel
  Revert "ACPICA: FADT support cleanup"

1 files changed, 4 insertions, 6 deletions

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;