File System Support; Watchdog Support - Kontron SMARC-sAMX8 User Manual

8.8. File System Support

SMARC sAMX8QM BSP supports the EXT2/EXT3 or EXT4 Root filesystem type in eMMC or SD. An image build
for sAMX8QM from the Yocto build system generates a U-Boot, kernel, and an image type based on the
"IMAGE_FSTYPES" defined in the machine configuration file. The default machine configuration file for sAMX8QM
generates an SD card image (.sdcard), an ext4 and tar.bz2. The ext4 is the root file system only. The .sdcard
image contains U-Boot, the kernel and the rootfs completely set up for use on an SD card

8.9. Watchdog Support

Linux kernel can reset the system via a hardware watchdog or a software watchdog when serious problems or failures
are detected. This can be achieved through a watchdog service or daemon which opens the /dev/watchdog and
refreshes it periodically to keep the kernel from resetting. When the daemon stops refreshing the watchdog the
watchdog times out and issues a system reset
SMARC sAMX8 BSP enables the watchdog daemon in background such that it keeps refreshing the hardware
watchdog /dev/watchdog periodically. The status of this service cab be checked using the below command
=> systemctl status watchdog
watchdog.service - watchdog daemon
Loaded: loaded (/lib/systemd/system/watchdog.service; enabled; vendor preset>
Active: active (running) since Fri 2019-11-08 08:52:49 UTC; 1min 39s ago
The Linux watchdog daemon not only refreshes the watchdog hardware periodically but also performs other system
checks as per the configurations in the watchdog.conf file and triggers a system reset when a failure in any of these
checks is encountered
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