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Commit e07fcfd8 authored by Bob Moore's avatar Bob Moore Committed by Rafael J. Wysocki
Browse files

ACPICA: Hardcode access width for the reset register. 



The ACPI spec requires the reset register width to be 8, so we
now hardcode it and ignore the FADT value. This provides/maintains
compatibility with other ACPI implementations that have allowed
BIOS code with bad register width values to go unnoticed.
Matthew Garett, Bob Moore, Lv Zheng.

Signed-off-by: default avatarBob Moore <robert.moore@intel.com>
Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent ab3b2480

drivers/acpi/acpica/hwxface.c

+8 −2
Original line number Diff line number Diff line
@@ -83,11 +83,17 @@ acpi_status acpi_reset(void) 
		 * For I/O space, write directly to the OSL. This bypasses the port

		 * validation mechanism, which may block a valid write to the reset

		 * register.

		 * Spec section 4.7.3.6 requires register width to be 8.

		 *

		 * NOTE:

		 * The ACPI spec requires the reset register width to be 8, so we

		 * hardcode it here and ignore the FADT value. This maintains

		 * compatibility with other ACPI implementations that have allowed

		 * BIOS code with bad register width values to go unnoticed.

		 */

		status =

		    acpi_os_write_port((acpi_io_address) reset_reg->address,

				       acpi_gbl_FADT.reset_value, 8);

				       acpi_gbl_FADT.reset_value,

				       ACPI_RESET_REGISTER_WIDTH);

	} else {

		/* Write the reset value to the reset register */

include/acpi/actypes.h

+1 −0
Original line number Diff line number Diff line
@@ -349,6 +349,7 @@ typedef u32 acpi_physical_address; 
#define ACPI_PM1_REGISTER_WIDTH         16

#define ACPI_PM2_REGISTER_WIDTH         8

#define ACPI_PM_TIMER_WIDTH             32

#define ACPI_RESET_REGISTER_WIDTH       8



/* Names within the namespace are 4 bytes long */