Commit 7954001a authored by Srinivas Pandruvada's avatar Srinivas Pandruvada Committed by Rafael J. Wysocki
Browse files

thermal: intel: int340x: Add throttling control interface to PTC 



Firmware-based thermal temperature control loops may aggressively
throttle performance to prevent temperature overshoots relative to the
defined target temperature. This can negatively impact performance. User
space may prefer to prioritize performance, even if it results in
temperature overshoots with in acceptable range.

For example, user space might tolerate temperature overshoots when the
device is placed on a desk, as opposed to when it's on a lap. To
accommodate such scenarios, an optional attribute is provided to specify
a tolerance level for temperature overshoots while maintaining acceptable
performance.

Attribute:

thermal_tolerance: This attribute ranges from 0 to 7, where 0 represents
the most aggressive control to avoid any temperature overshoots, and 7
represents a more graceful approach, favoring performance even at the
expense of temperature overshoots.
Note: This level may not scale linearly. For example, a value of 3 does not
necessarily imply a 50% improvement in performance compared to a value of 0.

Signed-off-by: default avatarSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Reviewed-by: default avatarZhang Rui <rui.zhang@intel.com>
Link: https://patch.msgid.link/20250613214923.2910397-1-srinivas.pandruvada@linux.intel.com


Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent e04c78d8

Documentation/driver-api/thermal/intel_dptf.rst

+9 −0
Original line number Diff line number Diff line
@@ -206,6 +206,15 @@ All these controls needs admin privilege to update. 
	Update a new temperature target in milli degree celsius for hardware to

	use for the temperature control.



``thermal_tolerance`` (RW)

	This attribute ranges from 0 to 7, where 0 represents

	the most aggressive control to avoid any temperature overshoots, and

	7 represents a more graceful approach, favoring performance even at

	the expense of temperature overshoots.

	Note: This level may not scale linearly. For example, a value of 3 does

	not necessarily imply a 50% improvement in performance compared to a

	value of 0.



Given that this is platform temperature control, it is expected that a

single user-level manager owns and manages the controls. If multiple

user-level software applications attempt to write different targets, it

drivers/thermal/intel/int340x_thermal/platform_temperature_control.c

+7 −1
Original line number Diff line number Diff line
@@ -49,7 +49,7 @@ struct mmio_reg { 
};



#define MAX_ATTR_GROUP_NAME_LEN	32

#define PTC_MAX_ATTRS		3

#define PTC_MAX_ATTRS		4



struct ptc_data {

	u32 offset;
@@ -57,6 +57,7 @@ struct ptc_data { 
	struct attribute *ptc_attrs[PTC_MAX_ATTRS];

	struct device_attribute temperature_target_attr;

	struct device_attribute enable_attr;

	struct device_attribute thermal_tolerance_attr;

	char group_name[MAX_ATTR_GROUP_NAME_LEN];

};
@@ -78,6 +79,7 @@ static u32 ptc_offsets[PTC_MAX_INSTANCES] = {0x5B20, 0x5B28, 0x5B30}; 
static const char * const ptc_strings[] = {

	"temperature_target",

	"enable",

	"thermal_tolerance",

	NULL

};
@@ -177,6 +179,8 @@ PTC_SHOW(temperature_target); 
PTC_STORE(temperature_target);

PTC_SHOW(enable);

PTC_STORE(enable);

PTC_SHOW(thermal_tolerance);

PTC_STORE(thermal_tolerance);



#define ptc_init_attribute(_name)\

	do {\
@@ -193,9 +197,11 @@ static int ptc_create_groups(struct pci_dev *pdev, int instance, struct ptc_data 


	ptc_init_attribute(temperature_target);

	ptc_init_attribute(enable);

	ptc_init_attribute(thermal_tolerance);



	data->ptc_attrs[index++] = &data->temperature_target_attr.attr;

	data->ptc_attrs[index++] = &data->enable_attr.attr;

	data->ptc_attrs[index++] = &data->thermal_tolerance_attr.attr;

	data->ptc_attrs[index] = NULL;



	snprintf(data->group_name, MAX_ATTR_GROUP_NAME_LEN,