PHYTEC
Page 40
You can use
to see a graphical overview of the cores and processes:
top
target$ htop
To power up the core again, execute:
target$ echo 1 > /sys/devices/system/cpu/cpu3/online
Suspend to RAM
The phyCORE-i.MX8MM supports basic suspend and resume. Different wake-up sources can be used.
Basically, suspend/resume is possible with:
target$ echo mem > /sys/power/state
#resume with pressing on/off button
To wakeup with serial console run:
target$ echo enabled > /sys/class/tty/ttymxc1/power/wakeup
target$ echo mem > /sys/power/state
Thermal Management
SoC Thermal Management
The
kernel has integrated thermal management which is capable of monitoring SoC temperatures, reducing the CPU frequency, driving fans,
Linux
advising other drivers to reduce the power consumption of devices, and – worst-case – shutting down the system gracefully (
/Documentation/thermal/sysfs-api.txt
This section describes how the thermal management kernel API is used for the i.MX 8M Plus SoC platform. The i.MX8 MP has two internal temperature
sensors for the SoC.
The current temperature can be read in Millicelsius with:
target$ cat /sys/class/thermal/thermal_zone0/temp
and
target$ cat /sys/class/thermal/thermal_zone1/temp
You will get, for example:
49000
There are two trip points registered by the
kernel driver:
imx8mm_thermal
: 85 °C type:
trip_point_0
passive
: 95 °C type:
trip_point_1
critical
(see kernel
folder
)
sysfs
/sys/class/thermal/thermal_zone0/
These trip points are used by the kernel thermal management to trigger events and change the cooling behavior. The following thermal policies (also
named
) are available in the kernel:
,
,
and
. The default policy used in the BSP is
.
thermal governors
Step Wise Fair Share Bang Bang,
User space
step_wise
If the value of the SoC temperature in the
file
is above
(greater than 85 °C), the CPU frequency is set to the lowest CPU
sysfs
temp
trip_point_0
frequency. When the SoC temperature drops below
again, the throttling is released.
trip_point_0
