Revert "ACPICA: FADT support cleanup"

Pavel Machek reports that commit 6ea8c546 (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: 6ea8c546 (ACPICA: FADT support cleanup)
Reported-by: NPavel Machek <pavel@ucw.cz>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

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;

include/acpi/actbl.h

@@ -230,72 +230,62 @@ struct acpi_table_facs {
 /* Fields common to all versions of the FADT */
 
 struct acpi_table_fadt {
-	struct acpi_table_header header;	/* [V1] Common ACPI table header */
-	u32 facs;		/* [V1] 32-bit physical address of FACS */
-	u32 dsdt;		/* [V1] 32-bit physical address of DSDT */
-	u8 model;		/* [V1] System Interrupt Model (ACPI 1.0) - not used in ACPI 2.0+ */
-	u8 preferred_profile;	/* [V1] Conveys preferred power management profile to OSPM. */
-	u16 sci_interrupt;	/* [V1] System vector of SCI interrupt */
-	u32 smi_command;	/* [V1] 32-bit Port address of SMI command port */
-	u8 acpi_enable;		/* [V1] Value to write to SMI_CMD to enable ACPI */
-	u8 acpi_disable;	/* [V1] Value to write to SMI_CMD to disable ACPI */
-	u8 s4_bios_request;	/* [V1] Value to write to SMI_CMD to enter S4BIOS state */
-	u8 pstate_control;	/* [V1] Processor performance state control */
-	u32 pm1a_event_block;	/* [V1] 32-bit port address of Power Mgt 1a Event Reg Blk */
-	u32 pm1b_event_block;	/* [V1] 32-bit port address of Power Mgt 1b Event Reg Blk */
-	u32 pm1a_control_block;	/* [V1] 32-bit port address of Power Mgt 1a Control Reg Blk */
-	u32 pm1b_control_block;	/* [V1] 32-bit port address of Power Mgt 1b Control Reg Blk */
-	u32 pm2_control_block;	/* [V1] 32-bit port address of Power Mgt 2 Control Reg Blk */
-	u32 pm_timer_block;	/* [V1] 32-bit port address of Power Mgt Timer Ctrl Reg Blk */
-	u32 gpe0_block;		/* [V1] 32-bit port address of General Purpose Event 0 Reg Blk */
-	u32 gpe1_block;		/* [V1] 32-bit port address of General Purpose Event 1 Reg Blk */
-	u8 pm1_event_length;	/* [V1] Byte Length of ports at pm1x_event_block */
-	u8 pm1_control_length;	/* [V1] Byte Length of ports at pm1x_control_block */
-	u8 pm2_control_length;	/* [V1] Byte Length of ports at pm2_control_block */
-	u8 pm_timer_length;	/* [V1] Byte Length of ports at pm_timer_block */
-	u8 gpe0_block_length;	/* [V1] Byte Length of ports at gpe0_block */
-	u8 gpe1_block_length;	/* [V1] Byte Length of ports at gpe1_block */
-	u8 gpe1_base;		/* [V1] Offset in GPE number space where GPE1 events start */
-	u8 cst_control;		/* [V1] Support for the _CST object and C-States change notification */
-	u16 c2_latency;		/* [V1] Worst case HW latency to enter/exit C2 state */
-	u16 c3_latency;		/* [V1] Worst case HW latency to enter/exit C3 state */
-	u16 flush_size;		/* [V1] Processor memory cache line width, in bytes */
-	u16 flush_stride;	/* [V1] Number of flush strides that need to be read */
-	u8 duty_offset;		/* [V1] Processor duty cycle index in processor P_CNT reg */
-	u8 duty_width;		/* [V1] Processor duty cycle value bit width in P_CNT register */
-	u8 day_alarm;		/* [V1] Index to day-of-month alarm in RTC CMOS RAM */
-	u8 month_alarm;		/* [V1] Index to month-of-year alarm in RTC CMOS RAM */
-	u8 century;		/* [V1] Index to century in RTC CMOS RAM */
-	u16 boot_flags;		/* [V3] IA-PC Boot Architecture Flags (see below for individual flags) */
-	u8 reserved;		/* [V1] Reserved, must be zero */
-	u32 flags;		/* [V1] Miscellaneous flag bits (see below for individual flags) */
-	/* End of Version 1 FADT fields (ACPI 1.0) */
-
-	struct acpi_generic_address reset_register;	/* [V3] 64-bit address of the Reset register */
-	u8 reset_value;		/* [V3] Value to write to the reset_register port to reset the system */
-	u16 arm_boot_flags;	/* [V5] ARM-Specific Boot Flags (see below for individual flags) (ACPI 5.1) */
-	u8 minor_revision;	/* [V5] FADT Minor Revision (ACPI 5.1) */
-	u64 Xfacs;		/* [V3] 64-bit physical address of FACS */
-	u64 Xdsdt;		/* [V3] 64-bit physical address of DSDT */
-	struct acpi_generic_address xpm1a_event_block;	/* [V3] 64-bit Extended Power Mgt 1a Event Reg Blk address */
-	struct acpi_generic_address xpm1b_event_block;	/* [V3] 64-bit Extended Power Mgt 1b Event Reg Blk address */
-	struct acpi_generic_address xpm1a_control_block;	/* [V3] 64-bit Extended Power Mgt 1a Control Reg Blk address */
-	struct acpi_generic_address xpm1b_control_block;	/* [V3] 64-bit Extended Power Mgt 1b Control Reg Blk address */
-	struct acpi_generic_address xpm2_control_block;	/* [V3] 64-bit Extended Power Mgt 2 Control Reg Blk address */
-	struct acpi_generic_address xpm_timer_block;	/* [V3] 64-bit Extended Power Mgt Timer Ctrl Reg Blk address */
-	struct acpi_generic_address xgpe0_block;	/* [V3] 64-bit Extended General Purpose Event 0 Reg Blk address */
-	struct acpi_generic_address xgpe1_block;	/* [V3] 64-bit Extended General Purpose Event 1 Reg Blk address */
-	/* End of Version 3 FADT fields (ACPI 2.0) */
-
-	struct acpi_generic_address sleep_control;	/* [V4] 64-bit Sleep Control register (ACPI 5.0) */
-	/* End of Version 4 FADT fields (ACPI 3.0 and ACPI 4.0) (Field was originally reserved in ACPI 3.0) */
-
-	struct acpi_generic_address sleep_status;	/* [V5] 64-bit Sleep Status register (ACPI 5.0) */
-	/* End of Version 5 FADT fields (ACPI 5.0) */
-
-	u64 hypervisor_id;	/* [V6] Hypervisor Vendor ID (ACPI 6.0) */
-	/* End of Version 6 FADT fields (ACPI 6.0) */
-
+	struct acpi_table_header header;	/* Common ACPI table header */
+	u32 facs;		/* 32-bit physical address of FACS */
+	u32 dsdt;		/* 32-bit physical address of DSDT */
+	u8 model;		/* System Interrupt Model (ACPI 1.0) - not used in ACPI 2.0+ */
+	u8 preferred_profile;	/* Conveys preferred power management profile to OSPM. */
+	u16 sci_interrupt;	/* System vector of SCI interrupt */
+	u32 smi_command;	/* 32-bit Port address of SMI command port */
+	u8 acpi_enable;		/* Value to write to SMI_CMD to enable ACPI */
+	u8 acpi_disable;	/* Value to write to SMI_CMD to disable ACPI */
+	u8 s4_bios_request;	/* Value to write to SMI_CMD to enter S4BIOS state */
+	u8 pstate_control;	/* Processor performance state control */
+	u32 pm1a_event_block;	/* 32-bit port address of Power Mgt 1a Event Reg Blk */
+	u32 pm1b_event_block;	/* 32-bit port address of Power Mgt 1b Event Reg Blk */
+	u32 pm1a_control_block;	/* 32-bit port address of Power Mgt 1a Control Reg Blk */
+	u32 pm1b_control_block;	/* 32-bit port address of Power Mgt 1b Control Reg Blk */
+	u32 pm2_control_block;	/* 32-bit port address of Power Mgt 2 Control Reg Blk */
+	u32 pm_timer_block;	/* 32-bit port address of Power Mgt Timer Ctrl Reg Blk */
+	u32 gpe0_block;		/* 32-bit port address of General Purpose Event 0 Reg Blk */
+	u32 gpe1_block;		/* 32-bit port address of General Purpose Event 1 Reg Blk */
+	u8 pm1_event_length;	/* Byte Length of ports at pm1x_event_block */
+	u8 pm1_control_length;	/* Byte Length of ports at pm1x_control_block */
+	u8 pm2_control_length;	/* Byte Length of ports at pm2_control_block */
+	u8 pm_timer_length;	/* Byte Length of ports at pm_timer_block */
+	u8 gpe0_block_length;	/* Byte Length of ports at gpe0_block */
+	u8 gpe1_block_length;	/* Byte Length of ports at gpe1_block */
+	u8 gpe1_base;		/* Offset in GPE number space where GPE1 events start */
+	u8 cst_control;		/* Support for the _CST object and C-States change notification */
+	u16 c2_latency;		/* Worst case HW latency to enter/exit C2 state */
+	u16 c3_latency;		/* Worst case HW latency to enter/exit C3 state */
+	u16 flush_size;		/* Processor memory cache line width, in bytes */
+	u16 flush_stride;	/* Number of flush strides that need to be read */
+	u8 duty_offset;		/* Processor duty cycle index in processor P_CNT reg */
+	u8 duty_width;		/* Processor duty cycle value bit width in P_CNT register */
+	u8 day_alarm;		/* Index to day-of-month alarm in RTC CMOS RAM */
+	u8 month_alarm;		/* Index to month-of-year alarm in RTC CMOS RAM */
+	u8 century;		/* Index to century in RTC CMOS RAM */
+	u16 boot_flags;		/* IA-PC Boot Architecture Flags (see below for individual flags) */
+	u8 reserved;		/* Reserved, must be zero */
+	u32 flags;		/* Miscellaneous flag bits (see below for individual flags) */
+	struct acpi_generic_address reset_register;	/* 64-bit address of the Reset register */
+	u8 reset_value;		/* Value to write to the reset_register port to reset the system */
+	u16 arm_boot_flags;	/* ARM-Specific Boot Flags (see below for individual flags) (ACPI 5.1) */
+	u8 minor_revision;	/* FADT Minor Revision (ACPI 5.1) */
+	u64 Xfacs;		/* 64-bit physical address of FACS */
+	u64 Xdsdt;		/* 64-bit physical address of DSDT */
+	struct acpi_generic_address xpm1a_event_block;	/* 64-bit Extended Power Mgt 1a Event Reg Blk address */
+	struct acpi_generic_address xpm1b_event_block;	/* 64-bit Extended Power Mgt 1b Event Reg Blk address */
+	struct acpi_generic_address xpm1a_control_block;	/* 64-bit Extended Power Mgt 1a Control Reg Blk address */
+	struct acpi_generic_address xpm1b_control_block;	/* 64-bit Extended Power Mgt 1b Control Reg Blk address */
+	struct acpi_generic_address xpm2_control_block;	/* 64-bit Extended Power Mgt 2 Control Reg Blk address */
+	struct acpi_generic_address xpm_timer_block;	/* 64-bit Extended Power Mgt Timer Ctrl Reg Blk address */
+	struct acpi_generic_address xgpe0_block;	/* 64-bit Extended General Purpose Event 0 Reg Blk address */
+	struct acpi_generic_address xgpe1_block;	/* 64-bit Extended General Purpose Event 1 Reg Blk address */
+	struct acpi_generic_address sleep_control;	/* 64-bit Sleep Control register (ACPI 5.0) */
+	struct acpi_generic_address sleep_status;	/* 64-bit Sleep Status register (ACPI 5.0) */
+	u64 hypervisor_id;	/* Hypervisor Vendor ID (ACPI 6.0) */
 };
 
 /* Masks for FADT IA-PC Boot Architecture Flags (boot_flags) [Vx]=Introduced in this FADT revision */
@@ -311,8 +301,8 @@ struct acpi_table_fadt {
 
 /* Masks for FADT ARM Boot Architecture Flags (arm_boot_flags) ACPI 5.1 */
 
-#define ACPI_FADT_PSCI_COMPLIANT    (1)	/* 00: [V5] PSCI 0.2+ is implemented */
-#define ACPI_FADT_PSCI_USE_HVC      (1<<1)	/* 01: [V5] HVC must be used instead of SMC as the PSCI conduit */
+#define ACPI_FADT_PSCI_COMPLIANT    (1)	/* 00: [V5+] PSCI 0.2+ is implemented */
+#define ACPI_FADT_PSCI_USE_HVC      (1<<1)	/* 01: [V5+] HVC must be used instead of SMC as the PSCI conduit */
 
 /* Masks for FADT flags */
 
@@ -409,34 +399,20 @@ struct acpi_table_desc {
  * match the expected length. In other words, the length of the
  * FADT is the bottom line as to what the version really is.
  *
- * NOTE: There is no officialy released V2 of the FADT. This
- * version was used only for prototyping and testing during the
- * 32-bit to 64-bit transition. V3 was the first official 64-bit
- * version of the FADT.
- *
- * Update this list of defines when a new version of the FADT is
- * added to the ACPI specification. Note that the FADT version is
- * only incremented when new fields are appended to the existing
- * version. Therefore, the FADT version is competely independent
- * from the version of the ACPI specification where it is
- * defined.
- *
- * For reference, the various FADT lengths are as follows:
- *     FADT V1 size: 0x074      ACPI 1.0
- *     FADT V3 size: 0x0F4      ACPI 2.0
- *     FADT V4 size: 0x100      ACPI 3.0 and ACPI 4.0
- *     FADT V5 size: 0x10C      ACPI 5.0
- *     FADT V6 size: 0x114      ACPI 6.0
+ * For reference, the values below are as follows:
+ *     FADT V1 size: 0x074
+ *     FADT V2 size: 0x084
+ *     FADT V3 size: 0x0F4
+ *     FADT V4 size: 0x0F4
+ *     FADT V5 size: 0x10C
+ *     FADT V6 size: 0x114
  */
-#define ACPI_FADT_V1_SIZE       (u32) (ACPI_FADT_OFFSET (flags) + 4)	/* ACPI 1.0 */
-#define ACPI_FADT_V3_SIZE       (u32) (ACPI_FADT_OFFSET (sleep_control))	/* ACPI 2.0 */
-#define ACPI_FADT_V4_SIZE       (u32) (ACPI_FADT_OFFSET (sleep_status))	/* ACPI 3.0 and ACPI 4.0 */
-#define ACPI_FADT_V5_SIZE       (u32) (ACPI_FADT_OFFSET (hypervisor_id))	/* ACPI 5.0 */
-#define ACPI_FADT_V6_SIZE       (u32) (sizeof (struct acpi_table_fadt))	/* ACPI 6.0 */
-
-/* Update these when new FADT versions are added */
+#define ACPI_FADT_V1_SIZE       (u32) (ACPI_FADT_OFFSET (flags) + 4)
+#define ACPI_FADT_V2_SIZE       (u32) (ACPI_FADT_OFFSET (minor_revision) + 1)
+#define ACPI_FADT_V3_SIZE       (u32) (ACPI_FADT_OFFSET (sleep_control))
+#define ACPI_FADT_V5_SIZE       (u32) (ACPI_FADT_OFFSET (hypervisor_id))
+#define ACPI_FADT_V6_SIZE       (u32) (sizeof (struct acpi_table_fadt))
 
-#define ACPI_FADT_MAX_VERSION   6
 #define ACPI_FADT_CONFORMANCE   "ACPI 6.1 (FADT version 6)"
 
 #endif				/* __ACTBL_H__ */