On Wed, 2020-09-02 at 06:36 -0700, Guenter Roeck wrote: > On 9/2/20 6:02 AM, Ivan Mikhaylov wrote: > > Hello everyone. Currently, the watchdog interface only has "stop watchdog on > > restart" but lacks a "start watchdog on restart" one. Is there a way to > > achieve > > such functionality? > > > > I'd like to know why "stop watchdog on restart" wasn't implemented via ioctl > > interface? It would be more convenient from user perspective and you can > > control that behavior whenever you want from application layer. > > > > Because it is and always was a driver level decision. The function was added > to replace lots of driver level code implementing this functionality. > Overriding it from userspace doesn't make sense because the driver is supposed > to have a reason for disabling it on reboot (for example due to clock issues > or power issues or becasue it has a short hardware timeout). If it's only driver level decision then it makes sense. > That functionality doesn't make much sense. It can be accomplished by not > stopping the watchdog on reboot in the first place. And if the watchdog > wasn't running before, it can be started from userspace just before the > reboot. I understand that it can be started from userspace. As example, I want the watchdog trigger with guarantee that the userspace will be properly shut on reboot, how can I get it with current interface? Just start before the reboot doesn't guarantee that it will be triggered or will be triggered in middle of reboot/restart. Thanks.
