Re: [PATCH v2] clocksource: timer-tegra186: Enable WDT at probe

[Daniel Lezcano <daniel.lezcano@linaro.org>]

On 08/07/2025 13:42, Jon Hunter wrote:
> 
> On 08/07/2025 12:22, Thierry Reding wrote:
>> On Tue, Jul 08, 2025 at 12:03:52AM +0200, Daniel Lezcano wrote:
>>> On 07/07/2025 23:19, Jon Hunter wrote:
>>>>
>>>> On 07/07/2025 10:51, Daniel Lezcano wrote:
>>>>> On Thu, Jul 03, 2025 at 04:34:15PM +0530, Kartik Rajput wrote:
>>>>>> Currently, if the system crashes or hangs during kernel boot before
>>>>>> userspace initializes and configures the watchdog timer, then the
>>>>>> watchdog won’t be able to recover the system as it’s not running. 
>>>>>> This
>>>>>> becomes crucial during an over-the-air update, where if the newly
>>>>>> updated kernel crashes on boot, the watchdog is needed to reset the
>>>>>> device and boot into an alternative system partition. If the watchdog
>>>>>> is disabled in such scenarios, it can lead to the system getting
>>>>>> bricked.
>>>>>>
>>>>>> Enable the WDT during driver probe to allow recovery from any 
>>>>>> crash/hang
>>>>>> seen during early kernel boot. Also, disable interrupts once 
>>>>>> userspace
>>>>>> starts pinging the watchdog.
>>>>>
>>>>> Please resend with proper recipients (linux-watchdog@, Wim Van
>>>>> Sebroeck, Guenter Roeck) and the changelog.
>>>>
>>>> ACK.
>>>>
>>>>> Can someone take the opportunity to split this watchdog code and move
>>>>> it in the proper watchdog drivers directory ?
>>>>
>>>> I understand that this was mentioned before, but Thierry previously
>>>> objected to this for this particular driver [0].
>>>
>>> Yes but meanwhile we found that the auxiliary device is designed for 
>>> this
>>> situation.
>>
>> Honestly, adding auxiliary bus into the mix is total overkill here. I
>> always thought with all the tools we have today it'd be easy enough to
>> have drivers spread across subsystems if that's what's best.
>>
>> But if y'all think this is the way, then sure, we'll do that.
> 
> 
> Yes we are happy to conform to whatever is preferred. However, this is 
> really a fix and IMO outside the scope of any refactoring work. I have 
> been pushing the necessary people at NVIDIA to get fixes upstream so 
> that any known issues are fixed. Hence, I would prefer to handle the 
> refactoring separately.


Yes, absolutely


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