Re: [PATCH] watchdog: enable systemd support

[Rongqing Li <rongqing.li@windriver.com>]

On 2016年01月22日 06:58, Randy MacLeod wrote:
> On 2016-01-19 09:01 PM, rongqing.li@windriver.com wrote:
>> 1. inherit systemd, and add two unit files which are from Fedora 23
>
> Fine.
>> 2. auto load soft dog kernel module
>
> I haven't used a hardware watchdog for a while. Does softdog
> abstract that away so that it's hidden by the BSP? If not,
> can a user ditch the softdog for a hardware watchdog? Does that
> over-ride process need to be documented?
>
>

Usually, watchdog timers are implemented as add-on cards, or as on-chip
peripherals within microcontrollers. But if there is no hardware watchdog,
the Linux kernel can provide a software watchdog implemented using kernel
timers.

https://en.wikibooks.org/wiki/The_Linux_Kernel/Softdog_Driver


if the machine has the hardware watchdog, and drivers are compiled in,
the /dev/watchdog will be generated; softdog is /dev/watchdog1 or
/dev/watchdog2, and the watchdog daemon will use the hardware watchdog


if drivers are compiled as module, udev will auto load it, but udev
will be run after systemd-modules-load.service, and softdog will be
used


-- 
Best Reagrds,
Roy | RongQing Li