From 4f41868116f1734d02aab68b6eb64a880727d9b6 Mon Sep 17 00:00:00 2001 From: Adam Nielsen Date: Sun, 4 Jul 2021 17:50:28 +1000 Subject: [PATCH 1/2] Update watchdog instructions for systemd --- Raspberry_Pi.md | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/Raspberry_Pi.md b/Raspberry_Pi.md index f3d73d0..17ed2ed 100644 --- a/Raspberry_Pi.md +++ b/Raspberry_Pi.md @@ -166,14 +166,16 @@ Where `` is: ### Watchdog BCM2708 has a hardware watchdog which can be utilized by enabling the -`bcm2708_wdog` kernel module. +`bcm2708_wdog` kernel module, `bcm2709_wdog` for the Pi 2, or `bcm2835_wdt` +for the Pi 3. In most cases these modules will load automatically. -For proper operation the watchdog daemon also has to be installed, configured -(by uncommenting the "watchdog-device" line in `/etc/watchdog.conf`) and -enabled. +To activate the watchdog, set the `RuntimeWatchdogSec` value in +`/etc/systemd/system.conf`. The largest permitted value is `15s` due to +hardware limitations. -This should also apply for Raspberry Pi 2 by using the `bcm2709_wdog` module -and Raspberry Pi 3 by using the `bcm2835_wdt` module. +The watchdog service is part of systemd, so no further configuration needs to +be done. `/etc/watchdog.conf` is no longer required as it was in the past, and +separate `systemctl` steps to enable and activate the service no longer apply. ## Hardware Random Number Generator Arch Linux ARM for the Raspberry Pi had the `bcm2708-rng` module set to load at From 5eea18580d5e322268d0270aa8123d23f9b3a474 Mon Sep 17 00:00:00 2001 From: Adam Nielsen Date: Sun, 4 Jul 2021 17:50:57 +1000 Subject: [PATCH 2/2] Add notes about getting a serial console working --- Raspberry_Pi.md | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/Raspberry_Pi.md b/Raspberry_Pi.md index 17ed2ed..c5f97cb 100644 --- a/Raspberry_Pi.md +++ b/Raspberry_Pi.md @@ -260,6 +260,12 @@ To use the GPIO/SPI pins as a regular non-root user (in group `tty`), add the fo SUBSYSTEM=="gpio", KERNEL=="gpiochip*", ACTION=="add", PROGRAM="/bin/sh -c 'chown root:tty /sys/class/gpio/export /sys/class/gpio/unexport ; chmod 220 /sys/class/gpio/export /sys/class/gpio/unexport'" SUBSYSTEM=="gpio", KERNEL=="gpio*", ACTION=="add", PROGRAM="/bin/sh -c 'chown root:tty /sys%p/active_low /sys%p/direction /sys%p/edge /sys%p/value ; chmod 660 /sys%p/active_low /sys%p/direction /sys%p/edge /sys%p/value'" +### Serial Console + +Adding `console=ttyAMA0,115200` to the kernel command line will enable it from +the kernel's perspective. On some models, the serial UART conflicts with the +Bluetooth UART, so disabling Bluetooth with `dtoverlay=disable-bt` in +`config.txt` may be required in order to get the serial console working. ## See Also