Merge tag 'acpi-4.7-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull ACPI fixes from Rafael Wysocki:
 "Two fixes for problems introduced recently (ACPICA and the ACPI
  backlight driver) and one fix for an older issue that prevents at
  least one system from booting.

  Specifics:

   - Fix an incorrect check introduced by recent ACPICA changes which
     causes problems with booting KVM guests to happen, among other
     things (Lv Zheng).

   - Fix a backlight issue introduced by recent changes to the ACPI
     video driver (Aaron Lu).

   - Fix the ACPI processor initialization which attempts to register an
     IO region without checking if that really is necessary and
     sometimes prevents drivers loaded subsequently from registering
     their resources which leads to boot issues (Rafael Wysocki)"

* tag 'acpi-4.7-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI / processor: Avoid reserving IO regions too early
  ACPICA / Hardware: Fix old register check in acpi_hw_get_access_bit_width()
  ACPI / Thermal / video: fix max_level incorrect value

1 files changed, 9 insertions, 14 deletions

diff --git a/drivers/acpi/acpica/hwregs.c b/drivers/acpi/acpica/hwregs.c
index 0f18dbc9a37f..daceb80022b0 100644
--- a/drivers/acpi/acpica/hwregs.c
+++ b/drivers/acpi/acpica/hwregs.c
@@ -83,27 +83,22 @@ acpi_hw_write_multiple(u32 value,
 static u8
 acpi_hw_get_access_bit_width(struct acpi_generic_address *reg, u8 max_bit_width)
 {
-	u64 address;
-
 	if (!reg->access_width) {
+		if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
+			max_bit_width = 32;
+		}
+
 		/*
 		 * Detect old register descriptors where only the bit_width field
-		 * makes senses. The target address is copied to handle possible
-		 * alignment issues.
+		 * makes senses.
 		 */
-		ACPI_MOVE_64_TO_64(&address, &reg->address);
-		if (!reg->bit_offset && reg->bit_width &&
+		if (reg->bit_width < max_bit_width &&
+		    !reg->bit_offset && reg->bit_width &&
 		    ACPI_IS_POWER_OF_TWO(reg->bit_width) &&
-		    ACPI_IS_ALIGNED(reg->bit_width, 8) &&
-		    ACPI_IS_ALIGNED(address, reg->bit_width)) {
+		    ACPI_IS_ALIGNED(reg->bit_width, 8)) {
 			return (reg->bit_width);
-		} else {
-			if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
-				return (32);
-			} else {
-				return (max_bit_width);
-			}
 		}
+		return (max_bit_width);
 	} else {
 		return (1 << (reg->access_width + 2));
 	}