L-1017e.A3 i.MX 8M Plus BSP Manual
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/etc/fancontrol
Fan control is started by a
systemd
service during boot. This can be disabled with:
target$ systemctl disable fancontrol
Device tree description of PWM Fan can be found here:
https://git.phytec.de/linux-imx/tree/arch/arm64/boot/dts/
freescale/imx8mp-phyboard-pollux.dtsi?h=v5.10.72_2.2.0-phy9#n37
Watchdog
The PHYTEC i.MX8MP modules include a hardware watchdog that is able to reset the board when the system hangs.
The watchdog is started on default in U-Boot with a timeout of 60s. So even during early kernel start, the watchdog
is already up and running. The Linux kernel driver takes control over the watchdog and makes sure that it is fed.
This section explains how to configure the watchdog in Linux using
systemd
to check for system hangs and during
reboot.
Watchdog Support in
systemd
Systemd
has included hardware watchdog support since version 183.
To activate watchdog support, the file
system.conf
in
/etc/systemd/
has to be adapted by enabling the
options:
RuntimeWatchdogSec=60s
ShutdownWatchdogSec=10min
RuntimeWatchdogSec
defines the timeout value of the watchdog, while
ShutdownWatchdogSec
defines the timeout
when the system is rebooted. For more detailed information about hardware watchdogs under
systemd
can be
found at
http://0pointer.de/blog/projects/watchdog.html
The changes will take into effect after a reboot or run:
target$ systemctl daemon-reload
snvs
Power Key
The X_ONOFF pin connected to the ON/OFF button can be pressed long to trigger Power OFF without SW
intervention or used to wake up the system out of suspend. With the
snvs_pwrkey
driver, the KEY_POWER event is
also reported to userspace when the button is pressed. On default,
systemd
is configured to ignore such events. The
function of Power OFF without SW intervention and the wake-up from suspend are not configured. Triggering a
power off with
systemd
when pushing the ON/OFF button can be configured under
/etc/systemd/logind.conf
and set
using:
HandlePowerKey=poweroff
