JP2013138041A - Electronic apparatus and fan control method of the same - Google Patents

Abstract

【Task】
An object of the present invention is to provide an electronic device and a fan control method capable of preventing excessive power consumption by appropriately controlling the rotation speed of a fan provided in the electronic device.
[Solution]
The electronic device includes a fan control unit and a threshold control unit. The fan control unit switches the rotation speed of the fan from low to high when the temperature in the housing becomes higher than the first threshold,
When the temperature falls below a second threshold, which is a temperature lower than the first threshold, the rotation speed of the fan is switched from high to low. The threshold control unit changes the second threshold.
[Selection] Figure 5

Description

  Embodiments described herein relate generally to an electronic device and a fan control method.

In recent years, CPUs (Central Processing Units) have been used in electrical devices such as computers and servers.
Since a device that generates heat such as a memory is built in, forced air cooling using a fan is used as an example of a method for cooling a heating element such as a CPU.

In the case of forced air cooling using a fan, a threshold value for controlling the rotation speed of the fan is set in advance. Then, the temperature in the housing is measured, and if the measured temperature in the housing is equal to or higher than the threshold value, the inside of the housing is cooled at a higher speed. The power is reduced.

At this time, if the temperature in the housing frequently exceeds the threshold value or returns to the range, the fan speed frequently changes. For this reason, a fan's roaring sound is generated, resulting in unpleasant noise.

For this reason, the threshold temperature is set to two values, and the temperature at which the fan is returned from the high rotation to the low rotation is lower than the temperature at which the fan is shifted from the low rotation to the high rotation, so that hysteresis is provided. ing. By providing hysteresis in this way, frequent changes in the fan speed can be prevented.

However, when hysteresis is provided, the threshold temperature at which the rotation speed of the fan is returned from the high rotation to the low rotation is effective once the temperature at which the fan is rotated at a high speed is exceeded. For this reason, if the temperature for returning the fan from high rotation to low rotation is not met, the low rotation speed of the fan is sufficient, but the rotation speed of the fan continues high rotation without shifting to low rotation. It will end up.

Japanese Examined Patent Publication No. 4-291

An object of the present invention is to provide an electronic device and a fan control method capable of preventing excessive power consumption by appropriately controlling the rotational speed of a fan provided in the electronic device.

According to the embodiment, the electronic device includes a fan control unit and a threshold control unit. The fan control unit switches the rotation speed of the fan from low rotation to high rotation when the temperature in the housing becomes higher than the first threshold, and the second threshold is a temperature lower than the first threshold. Thus, when the temperature falls, the rotational speed of the fan is switched from high rotation to low rotation. The threshold control unit
The second threshold value is changed.

The figure which showed the front of the electronic device 1 in embodiment. 1 is a block configuration diagram of an electronic apparatus 1 according to an embodiment. The figure which shows the general operation | movement of the rotation speed control of the fan 22. FIG. The flowchart which shows operation | movement at the time of adjusting a 2nd threshold value. The figure which shows the operation | movement in the case of adjusting a 2nd threshold value. The flowchart for demonstrating operation | movement of the 1st step of fan adjustment transfer mode. The flowchart which shows operation | movement of fan adjustment 1st mode (threshold rise mode). The flowchart which shows operation | movement of the fan adjustment 2nd mode (threshold fall mode).

  Hereinafter, embodiments will be described with reference to the drawings.

FIG. 1 is a diagram illustrating the front of an electronic device 1 according to an embodiment. In the figure, an electronic device 1 is an information device such as a server device or a personal computer. A slot 3 for connecting a storage unit or the like such as a memory card recording / reproducing device, a fan control button 4, etc.
A fan control notification LED 5 is arranged.

Here, the fan control button 4 is an operation unit for switching a fan mode. Here, the fan mode is set to the first threshold value (temperature to be changed from low rotation to high rotation) and the second threshold value (temperature to be changed from high rotation to low rotation) set by default. “Fan normal mode” to be controlled, “Fan adjustment mode” to continue the operation in a state where the second threshold is adjusted, “Fan adjustment transition mode” for adjusting the second threshold to shift to the fan adjustment mode "I will take one of the modes."

The fan control notification LED 5 functions as a display unit for notifying the fan adjustment transition mode and the fan adjustment mode. For example, the LED blinks when in the “fan adjustment transition mode” for changing the threshold value, and is lit when in the “fan adjustment mode”, which is the mode after the adjustment of the threshold value. As another lighting method, the “fan adjustment transition mode” and the “fan adjustment mode” may be lit in different colors.

FIG. 2 is a block configuration diagram of the electronic apparatus 1 according to the embodiment. The electronic device 1 is a CPU 1
1, North Bridge 12, main memory 13, PCIe (Peripheral Component Interconnec
t Express) slot 14, south bridge 15, BIOS (Basic Input Output System)
) A flash memory 16, an HDD (Hard Disk Drive) 17, and an embedded controller (EC) 20 are provided. The embedded controller (EC) 20 includes a fan control button 4, a notification LED 5, a temperature sensor 21, a fan 22, a BMC (Baseboard Management).
Controller) A flash memory 23 and a power supply circuit 24 are connected. Here, the temperature sensor 21 is provided in the vicinity of the CPU 11 in order to measure the temperature of the CPU 11.

The CPU 11 is a processor provided for controlling the operation of the electronic device 1, and the HD
An operating system (OS) and various application programs loaded from the D17 to the main memory 13 are executed. The main memory 13 is also used for storing various data buffers.

The CPU 11 also executes the system BIOS stored in the BIOS flash memory 16. The system BIOS is a program for hardware control.

The north bridge 12 is a bridge device that connects the local bus of the CPU 11 and the south bridge 15. The north bridge 12 includes a memory controller that controls access to the main memory 13. The north bridge 12 is connected to the slot 3 via a PCIe bus or the like, and has a function of executing communication with a connected graphics controller or the like.

The south bridge 15 is an LPC (Low Pin Count) bus, PCI (Peripheral Componen).
Controls each device on t Interconnect (bus interconnect) and USB (Universal Serial Bus). The south bridge 15 is a PC for communicating with a device connected to the PCIe bus.
Built-in Ie controller. Further, the south bridge 15 has a function for controlling access to the BIOS flash memory 16. The HDD 17 stores the OS and various application programs.

The EC 20 includes functions of a keyboard controller (KBC) 25 for controlling the fan control button 4, the fan control notification LED 5, and the like, and a baseboard management controller (BMC, Baseboard Management Controller) 26 for power control and temperature control. A one-chip microcomputer. The KBC 25 may be a controller called Super-I / O. The BMC 26 has a function of turning on / off the electronic device 1 in accordance with the operation of the power switch by the user in cooperation with the power supply circuit 4.

BMC 26 is an industry standard IPMI (Intelligent Platform Management Interface)
It corresponds to the specification. The BMC 26 is a control unit that performs hardware event recording (Log) in addition to power supply monitoring and voltage monitoring of the power supply circuit 24. The control program for the BMC 26 is
It is stored in the BMC flash memory 23. Further, the BMC 26 controls the rotation of the fan 22 based on the temperature of the power supply circuit 24, the inside of the casing, the CPU 11, and the vicinity thereof. For this purpose, the BMC 26 stores in the BMC flash memory 16 a first threshold value that is a temperature that shifts from low rotation to high rotation and a second threshold value that shifts from low rotation to high rotation.

When the electronic device 1 is in an operating state, the BMC 26
The temperature of the CPU 11 and its vicinity is monitored by the temperature sensor 21, and the detected temperature is compared with the first threshold value and the second threshold value, thereby determining the rotational speed of the fan 22, and the fan 22
The number of revolutions is controlled by notifying to.

  Next, the operation of the present embodiment will be described.

  FIG. 3 is a diagram illustrating a general operation for controlling the rotational speed of the fan 22.

In the figure, the horizontal axis represents time, and the vertical axis represents ambient environmental temperature. Here, the ambient environment temperature is a temperature detected by a temperature sensor. The first threshold value 27 is a temperature that is a threshold value for changing the rotation speed of the fan 22 from a low rotation to a high rotation. The second threshold value 28 is a temperature that is a threshold value for returning the rotation speed of the fan 22 from high rotation to low rotation. Here, the second threshold value is set to a temperature lower than the first threshold value in order to give hysteresis to the control of the fan rotation speed.

Next, the temporal transition of the fan rotation speed will be described. First, in the state 31, the fan is in a low rotation. Due to the heat generated by the CPU 11 and the like due to the operation of the electronic device, the ambient environment temperature starts to rise in 32 hours. At this point, the fan is still maintaining low rotation. Next, at time 33, the ambient environment temperature exceeds the first threshold value 27. When detecting this, the BMC 26 shifts the fan 22 to high rotation.

At 34, the ambient temperature begins to drop due to external factors such as air conditioning. However, at this time, the high fan rotation is maintained. Thereafter, the ambient environment temperature continues to fall, and at the time of 35, the ambient temperature falls below the first threshold value (temperature at which the fan shifts from low rotation to high rotation) 27. However, since the first threshold value is not the temperature at which the high rotation is shifted to the low rotation, the fan 22 continues to maintain the high rotation. At 36, the temperature stops decreasing, and the ambient temperature drops to the same level as at 31, but the fan 22 maintains high rotation.

Then, the fan 22 continues to operate at a high speed, so that the cooling effect is effective, and the temperature becomes lower than the second threshold 28 at 37. Here, since the second threshold value 28 is a temperature at which the fan 22 is returned from high rotation to low rotation, the fan 22 is shifted to low rotation.

For this reason, from the time point 35 to the time point 37, the high rotation is continued despite the ambient temperature that is possible even if the fan 22 is at a low speed.

  FIG. 4 is a flowchart showing an operation when adjusting the second threshold value.

In the figure, the BMC 26 monitors whether the fan control button 4 has been continuously pressed for a predetermined time or longer (hereinafter referred to as “long press”) via the KBC 25. If a long press is detected (step 401), the mode shifts to the “fan adjustment transition mode” and the notification LED 5 blinks (step 402). Here, the reason why the transition to the “fan adjustment transition mode” is switched by long-pressing the fan control button 4 is to prevent an erroneous operation.

The BMC 26 monitors the depression of the fan control button 4 (step 403), and increments the number of times each time the fan control button 4 is depressed (step 404). If it is within a predetermined time (for example, m seconds) from the pressing of the fan control button 4, the process returns to step 401, and the pressing of the fan control button 4 is continuously monitored (step 405). When a predetermined time (for example, m seconds) has elapsed since the fan control button 4 was pressed, it is determined that the process has ended,
The number of times the fan control button 4 is pressed is determined (step 406). Here, not a long press but a normal press is monitored.

Here, the control differs depending on the number of times the fan control button 4 is pressed. In step 406,
If pressed once, the temperature setting (second threshold) at which the fan returns from high rotation to low rotation is increased by n degrees (step 407). If the fan is pressed twice in step 406, the temperature setting (second threshold value) at which the fan returns from high rotation to low rotation is increased by 2n degrees (step 408). Here, n is a unit for temperature control, and for example, n = 1 ° C. or n = 5 ° C. is set in advance.

And it transfers to fan adjustment mode (step 409). Then, the notification LED 5 shifts from blinking to lighting, and the SEL (System Ev) is sent to the BMC (Baseboard Management Controller).
ent Log) leaves a control start event as an OEM event in each mode (step 410).
Thereafter, the rotation speed of the fan 22 is controlled based on the adjusted second threshold 28.

If it has been pressed three times in step 406, it is determined whether or not the rotational speed of the fan 22 at that time is the slowest rotational speed (step 411). At this time, if it is not the slowest rotational speed, the rotational speed of the fan is lowered by one step (step 412), and the process proceeds to step 410.

In step 406, when the fan control button is pressed four times or more, or in step 41
If the fan speed is the slowest at 1, the fan adjustment transition mode is terminated (step 413) and the normal mode is entered. Then, the blinking notification LED 5 is turned off (step 414).

  FIG. 5 is a diagram illustrating an operation when the second threshold value is adjusted.

In the figure, the horizontal axis represents time and the vertical axis represents the ambient temperature. Here, the ambient environment temperature is a temperature detected by a temperature sensor. The first threshold value 27 is a temperature that is a threshold value for changing the rotational speed of the fan from a low speed to a high speed. The second threshold value 28 is a temperature that is a threshold value for returning the rotation speed of the fan from high rotation to low rotation. The second threshold 28 is set to a temperature lower than the first threshold 27 in order to give hysteresis to the control of the rotational speed.

At time 51, the fan 22 is running at a low speed, and the ambient environment temperature starts to rise due to heat generated by the CPU or the like due to the operation of the electronic device. Next, at time 52, the ambient temperature exceeds the first threshold value 27. When the BMC 26 detects this, the fan 22 shifts to high rotation. At 53, the ambient environment temperature starts to drop due to external factors such as air conditioning. But,
At this time, the high fan rotation is maintained.

The ambient temperature continues to fall, and at 54, the ambient temperature drops below the first threshold value (temperature at which the fan shifts from low rotation to high rotation) 27. Even at this time, the BMC 26 maintains the fan 22 at a high speed. Thereafter, the ambient environment temperature fluctuates above and below the first threshold 27, but the BMC 26 maintains the fan 22 at a high speed.

It is assumed that at time 55, the user performs an operation of changing the second threshold 28 according to the procedure of FIG. When this is detected via the KBC 25, the BMC 26 changes the second threshold 28 stored in the BMC flash 23.

Thereafter, the ambient temperature decreases and falls below the second threshold 28 at 56. For this reason, the BMC 26 reduces the rotational speed of the fan 22 by one step at this time to make the rotation low. 5
Although the second threshold value 28 is exceeded at the time point 7, the BMC 26 maintains the low rotation speed of the fan 22. Thereafter, the temperature decreases and falls below the second threshold value before adjustment at 58. Even at this time, in the BMC 26, the fan maintains a low speed.

As shown in the figure, since the user increased the second threshold value 28 at the time point 55, before the adjustment of the second threshold value 28, the high rotation is maintained until the time point 58. It can shift to low rotation. Therefore, since the rotation speed between 56-58 can be reduced, noise can be reduced and power consumption can be reduced.

In the present embodiment, if it is desired to further advance the transition from the high rotation to the low rotation, it can be achieved by shifting again to the fan adjustment transition mode and raising the second threshold value. On the other hand, if it is desired to lower the second threshold value, in step 406 of FIG. 4, the fan control button 4 is pressed four times or more to exit from the fan adjustment mode to the fan normal mode. Can be restored to value.

<Second Embodiment>
Next, a second embodiment will be described.

In the first embodiment, when it is desired to lower the second threshold, it is necessary to exit from the fan adjustment mode. On the other hand, the present embodiment is an embodiment in which control for lowering the second threshold is also possible.

In the second embodiment, the fan adjustment transition mode has two stages. The first stage is a stage in which one of “an operation to increase the second threshold value”, “an operation to decrease the second threshold value”, and “an operation to exit from the fan adjustment mode” is selected in the fan adjustment selection mode. The second stage includes two types of “fan adjustment first mode” that is control for increasing the second threshold value and “fan adjustment second mode” that is control for decreasing the second threshold value.

Since the configuration of the present embodiment is the same as that of the first embodiment, description thereof is omitted.

  The operation of the second embodiment will be described.

  6, 7 and 8 are flowcharts for explaining the operation of the second embodiment.

FIG. 6 is a flowchart for explaining the operation in the first stage of the fan adjustment transition mode.

In the figure, the BMC 26 monitors whether the fan control button 4 has been pressed for a long time via the KBC 25. Here, when a long press is detected (step 601), the mode shifts to the “fan adjustment transition mode” and the notification LED 5 blinks (step 602). Here, the reason why the transition to the “fan adjustment selection mode” is switched by long-pressing the fan control button 4 is to prevent an erroneous operation.

The BMC 26 monitors the depression of the fan control button 4 (step 603), and increments the number of times each time the fan control button 4 is depressed (step 404). Then, the process returns to step 601 until the fan control button 4 is pressed for a long time, and the depression of the fan control button 4 is continuously monitored (step 605). The reason for detecting the long press in step 605 is to clarify the break in operation with the second stage described later.

If a long press of the fan control button 4 is detected, it is determined that the process is finished, and the number of times the fan control button 4 is pressed is determined (step 606).

Here, the control differs depending on the number of times the fan control button 4 is pressed. In step 606,
When pressed once, the process proceeds to the “fan adjustment first mode” which is a control for increasing the temperature setting (second threshold value) at which the fan returns from high rotation to low rotation (step 607). Step 60
In step 6, when the button is pressed twice, the process proceeds to the “fan adjustment second mode” which is a control for lowering the temperature setting (second threshold) at which the fan returns from the high rotation to the low rotation (step 608).

If it is determined in step 606 that the fan control button 4 has been pressed three times or more, the fan adjustment transition mode is terminated (step 609) and the normal mode is entered. Then, the blinking notification LED 5 is turned off (step 610).

FIG. 7 is a flowchart showing the operation of the first fan adjustment mode (threshold increase mode).

In the figure, the BMC 26 monitors the depression of the fan control button 4 (step 702) in the state of transition to the first fan adjustment mode (threshold increase mode) (step 701), and every time the fan control button 4 is depressed. Then, the number of times is incremented (step 703).
If it is within a predetermined time (for example, m seconds) from the pressing of the fan control button 4, the process returns to step 701, and the pressing of the fan control button 4 is continuously monitored (step 704).
When a predetermined time (for example, m seconds) has elapsed since the pressing of the fan control button 4, it is determined that the process has ended, and the number of times the fan control button 4 is pressed is determined (step 705). Here, not a long press but a normal press is monitored.

Here, the control differs depending on the number of times the fan control button 4 is pressed. In step 705,
If pressed once, the temperature setting (second threshold) at which the fan returns from high rotation to low rotation is increased by n degrees (step 706). If the fan is pressed twice in step 705, the temperature setting (second threshold value) at which the fan returns from high rotation to low rotation is increased by 2n degrees (step 707). Here, n is a unit for temperature control, and for example, n = 1 ° C. or n = 5 ° C. is set in advance.

Then, the mode shifts to the fan adjustment mode (step 708). Then, the notification LED 5 shifts from blinking to lighting, and the SEL (System Ev) is sent to the BMC (Baseboard Management Controller).
ent Log) leaves a control start event as an OEM event in each mode (step 709).
Thereafter, the rotation speed of the fan 22 is controlled based on the adjusted second threshold 28.

In step 705, if it is pressed three times or more, it is determined whether or not the rotational speed of the fan 22 at that time is the slowest rotational speed (step 710). At this time, if it is not the slowest rotational speed, the rotational speed of the fan is lowered by one step (step 711), and the process proceeds to step 709.

  If the fan speed is the slowest in step 710, the process ends.

FIG. 8 is a flowchart showing the operation of the second fan adjustment mode (threshold lowering mode).

In FIG. 8, “increase n degrees” in step 706 is “decrease n degrees” in step 806. Similarly, “Increase 2n degrees” in Step 707 is changed to “2n” in Step 806.
"Decrease". Except for these two points, the description is omitted because it is the same as FIG.

For this reason, the opportunity to rotate the fan at high speed is reduced, and noise and consumption of commercial power can be suppressed.

<Modification>
In the first embodiment and the second embodiment, the transition to the fan control mode and the adjustment value of the second threshold value are performed by pressing the fan control button 4, but the present invention is not limited to this. For example, a maintenance terminal may be connected to the electronic device 1 and the second threshold value may be directly input.

Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

DESCRIPTION OF SYMBOLS 1 ... Electronic device 2 ... Housing 3 ... Slot 4 ... Fan control button 5 ... Fan control notification LED
11 ... CPU15
12 ... North bridge 13 ... Main memory 15 ... South bridge 16 ... BIOS flash memory 17 ... HDD
20 ... Embedded controller (EC)
21 ... Temperature sensor 22 ... Fan 23 ... BMC flash memory 24 ... Power supply circuit 25 ... Keyboard controller (KBC)
26 ... Baseboard management controller (BMC)
26 Heat conduction member

Claims (16)

In electronic equipment with a fan that air-cools the inside of the housing,
When the temperature in the housing becomes higher than the first threshold, the rotation speed of the fan is switched from low to high, and the temperature drops below the second threshold, which is lower than the first threshold. A fan control unit that switches the rotation speed of the fan from high rotation to low rotation,
An electronic device comprising: a threshold control unit that changes the second threshold. The operation unit of the threshold control unit includes a fan control button,
The electronic device according to claim 1, wherein when the fan control button is pressed for a predetermined time or more, the electronic device shifts to a threshold control mode for controlling the threshold. The threshold control unit includes:
The number of times the fan control button has been pressed after entering the threshold control mode is
If it is less than or equal to the first predetermined number of times, control to increase the temperature of the threshold corresponding to the number of times pressed,
If it is greater than the first predetermined number of times and less than the second predetermined number of times, control is performed to reduce the rotational speed of the fan,
The electronic device according to claim 2, wherein when the number is greater than the second predetermined number of times, control to exit from the threshold control mode is performed. The threshold control mode is:
6. After entering the threshold control mode, the control unit selects one of a threshold increase mode for increasing the threshold, a threshold decrease mode for decreasing the threshold, and control for exiting the threshold control mode according to the number of times the fan control button is pressed. 2. The electronic device according to 2. The threshold control unit includes:
When entering the threshold control mode after entering the threshold control mode, the number of times the fan control button has been pressed is
In the case of the third predetermined number or less, control is performed to increase the temperature of the threshold corresponding to the number of times of pressing,
The electronic device according to claim 4, wherein when the number is less than the third predetermined number of times, control is performed to reduce the rotational speed of the fan. The threshold control unit includes:
If the threshold control mode is entered after entering the threshold control mode, the number of times the fan control button has been pressed is
If the number of times is equal to or less than the fourth predetermined number of times, control is performed to increase the temperature of the threshold corresponding to the number of times of pressing,
The electronic apparatus according to claim 4, wherein when the number is less than the fourth predetermined number of times, control is performed to reduce the rotational speed of the fan. The electronic device according to claim 1, wherein the housing includes a notification LED that notifies the transition to the threshold control mode. The notification LED is a notification LED that is lit by the first lighting method when the threshold control mode is entered, and that is lit by the second lighting method after the threshold setting is completed. Electronic equipment. In a fan control method for an electronic device having a fan for air-cooling the inside of a housing,
A first threshold value for switching the rotational speed of the fan from a low speed to a high speed, and a second threshold value that is a temperature lower than the first threshold value for switching the rotational speed of the fan from a high speed to a low speed Set
In response to an operation by the operation unit, the mode shifts to a threshold control mode for changing the second threshold, and the second threshold is set.
The temperature inside the housing is detected, and when the temperature becomes higher than the first threshold, the rotational speed of the fan is switched from low to high. When the temperature falls below the second threshold, the rotational speed of the fan is changed. Electronic device fan control method that switches from high rotation to low rotation. The electronic device fan control method according to claim 9, wherein the control of the operation unit shifts to the threshold control mode for controlling a threshold when the fan control button is pressed for a predetermined time or more. The control of the threshold control unit is
Count the number of times the fan control button was pressed after entering the threshold control mode,
If the number of times the fan control button is pressed is equal to or less than the first predetermined number, the control is performed to increase the temperature of the threshold corresponding to the number of times pressed.
If the number of times the fan control button has been pressed is greater than the first predetermined number of times and less than the second predetermined number of times, control is performed to reduce the rotational speed of the fan,
The electronic device fan control method according to claim 2, wherein when the number of times the fan control button is pressed is greater than a second predetermined number of times, control to exit from the threshold control mode is performed. The threshold control mode is:
After entering the threshold control mode, count the number of times the fan control button is pressed,
11. The fan control of the electronic device according to claim 10, wherein the number of times the fan control button is pressed selects one of a threshold increase mode for increasing a threshold, a threshold decrease mode for decreasing a threshold, and control for exiting the threshold control mode. Method. The control of the threshold control unit is as follows:
When entering the threshold control mode after entering the threshold control mode, the number of times the fan control button has been pressed is
In the case of the third predetermined number or less, control is performed to increase the temperature of the threshold corresponding to the number of times of pressing,
13. The fan control method for an electronic device according to claim 12, wherein when the number is smaller than the third predetermined number of times, control is performed to reduce the rotation speed of the fan. The control of the threshold control unit is as follows:
If the threshold control mode is entered after entering the threshold control mode, the number of times the fan control button has been pressed is
If the number of times is equal to or less than the fourth predetermined number of times, control is performed to increase the temperature of the threshold corresponding to the number of times of pressing,
The electronic device fan control method according to claim 12, wherein when the number is less than the fourth predetermined number of times, control is performed to reduce the rotation speed of the fan. The transition to the threshold control mode is a notification L for notifying the transition to the threshold control mode.
The electronic device fan control method according to claim 9, wherein the ED is lit. When the threshold control mode is entered, when the threshold control mode is entered, the notification LED is turned on by the first lighting method, and after the threshold setting is completed, the notification LED is turned on for the second time. The information processing apparatus fan control method according to claim 15, wherein the notification LED is turned on by the method.

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