Files
linux-stable-mirror/drivers/acpi/fan.h
Armin Wolf 84a8b8f53b ACPI: fan: Workaround for 64-bit firmware bug
[ Upstream commit 2e00f7a4bb ]

Some firmware implementations use the "Ones" ASL opcode to produce
an integer with all bits set in order to indicate missing speed or
power readings. This however only works when using 32-bit integers,
as the ACPI spec requires a 32-bit integer (0xFFFFFFFF) to be
returned for missing speed/power readings. With 64-bit integers the
"Ones" opcode produces a 64-bit integer with all bits set, violating
the ACPI spec regarding the placeholder value for missing readings.

Work around such buggy firmware implementation by also checking for
64-bit integers with all bits set when reading _FST.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
[ rjw: Typo fix in the changelog ]
Link: https://patch.msgid.link/20251007234149.2769-3-W_Armin@gmx.de
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-01-08 10:13:56 +01:00

105 lines
2.7 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* ACPI fan device IDs are shared between the fan driver and the device power
* management code.
*
* Add new device IDs before the generic ACPI fan one.
*/
#ifndef _ACPI_FAN_H_
#define _ACPI_FAN_H_
#include <linux/kconfig.h>
#include <linux/limits.h>
#define ACPI_FAN_DEVICE_IDS \
{"INT3404", }, /* Fan */ \
{"INTC1044", }, /* Fan for Tiger Lake generation */ \
{"INTC1048", }, /* Fan for Alder Lake generation */ \
{"INTC1063", }, /* Fan for Meteor Lake generation */ \
{"INTC106A", }, /* Fan for Lunar Lake generation */ \
{"INTC10A2", }, /* Fan for Raptor Lake generation */ \
{"PNP0C0B", } /* Generic ACPI fan */
#define ACPI_FPS_NAME_LEN 20
struct acpi_fan_fps {
u64 control;
u64 trip_point;
u64 speed;
u64 noise_level;
u64 power;
char name[ACPI_FPS_NAME_LEN];
struct device_attribute dev_attr;
};
struct acpi_fan_fif {
u8 revision;
u8 fine_grain_ctrl;
u8 step_size;
u8 low_speed_notification;
};
struct acpi_fan_fst {
u64 revision;
u64 control;
u64 speed;
};
struct acpi_fan {
acpi_handle handle;
bool acpi4;
bool has_fst;
struct acpi_fan_fif fif;
struct acpi_fan_fps *fps;
int fps_count;
struct thermal_cooling_device *cdev;
struct device_attribute fst_speed;
struct device_attribute fine_grain_control;
};
/**
* acpi_fan_speed_valid - Check if fan speed value is valid
* @speeed: Speed value returned by the ACPI firmware
*
* Check if the fan speed value returned by the ACPI firmware is valid. This function is
* necessary as ACPI firmware implementations can return 0xFFFFFFFF to signal that the
* ACPI fan does not support speed reporting. Additionally, some buggy ACPI firmware
* implementations return a value larger than the 32-bit integer value defined by
* the ACPI specification when using placeholder values. Such invalid values are also
* detected by this function.
*
* Returns: True if the fan speed value is valid, false otherwise.
*/
static inline bool acpi_fan_speed_valid(u64 speed)
{
return speed < U32_MAX;
}
/**
* acpi_fan_power_valid - Check if fan power value is valid
* @power: Power value returned by the ACPI firmware
*
* Check if the fan power value returned by the ACPI firmware is valid.
* See acpi_fan_speed_valid() for details.
*
* Returns: True if the fan power value is valid, false otherwise.
*/
static inline bool acpi_fan_power_valid(u64 power)
{
return power < U32_MAX;
}
int acpi_fan_get_fst(acpi_handle handle, struct acpi_fan_fst *fst);
int acpi_fan_create_attributes(struct acpi_device *device);
void acpi_fan_delete_attributes(struct acpi_device *device);
#if IS_REACHABLE(CONFIG_HWMON)
int devm_acpi_fan_create_hwmon(struct device *dev);
#else
static inline int devm_acpi_fan_create_hwmon(struct device *dev) { return 0; };
#endif
#endif