Best practice when probe fails on armed watchdog?

Best practice when probe fails on armed watchdog?

[Ulrich Hecht]

Hi!

What is the right thing to do when a watchdog device that has been armed by the bootloader fails to probe? Should the driver

- disable the device and thus save the system from being torn down by a potentially malfunctioning watchdog, at the risk of missing issues further down the line, or
- leave it as is (even though that would most likely result in a reset), hoping that the error is either transient or that there is a mechanism in place outside the kernel that will resolve it?

Is there a best practice for this case?

CU
Uli

Re: Best practice when probe fails on armed watchdog?

[Guenter Roeck]

On Wed, Jan 29, 2020 at 06:16:19PM +0100, Ulrich Hecht wrote:
> Hi!
> 
> What is the right thing to do when a watchdog device that has been armed by the bootloader fails to probe? Should the driver
> 
> - disable the device and thus save the system from being torn down by a potentially malfunctioning watchdog, at the risk of missing issues further down the line, or
> - leave it as is (even though that would most likely result in a reset), hoping that the error is either transient or that there is a mechanism in place outside the kernel that will resolve it?
> 
> Is there a best practice for this case?
> 

I'd first ask _why_ the watchdog fails to probe. It may well be that
the hardware simply does not exist, or that the provided address points
to something else. Since that can happen, the driver should probably
not touch the HW at all if instantiating it fails. 

Guenter