Re: [PATCH v1 0/6] Introduce power off call chain API

[Dmitry Osipenko]

07.10.2021 12:11, Andy Shevchenko пишет:
> On Thu, Oct 07, 2021 at 11:52:46AM +0300, Dmitry Osipenko wrote:
>> 07.10.2021 10:18, Andy Shevchenko пишет:
>>> On Thu, Oct 7, 2021 at 9:05 AM Dmitry Osipenko <digetx@xxxxxxxxx> wrote:
> 
> ...
> 
>>>> This
>>>> is a somewhat simplified version which doesn't try to convert whole kernel
>>>> to the new API at once, but solves immediate practical problem that we
>>>
>>> problems
>>>
>>>> have on Nexus 7 Android tablet where device needs to chain power off
>>>
>>> tablets where the device
>>
>> Thank you for the corrections, so far there is one problem and one tablet :)
> 
> Then use "the Nexus 7 Android tablet" :-)
> 
>>> Immediate question here is how do you see the plan of spreading this.
>>> I.o.w. can you put an explanation that you have checked, let's say
>>>> 80% current users, and they may be converted like [example
>>> placeholder] without any special tricks?
>>
>> The rough plan is:
>>
>> 1. Add new API.
>> 2. Convert drivers to the new API per subsystem.
> 
> I would suggest to show that you are actually into it by converting a couple of
> the subsystems for the starter.

Noted

>> 3. Expose do_kernel_restart().
>> 4. Replace pm_power_off() with do_kernel_poweroff() per arch/, making
>> power off similar to the restart that uses do_kernel_restart().
>> 5. Remove do_kernel_restart() from kernel/reboot.c
>>
>> Majority of pm_power_off() users shouldn't need the chaining and
>> pm_power_off() doesn't conflict with the new API, so there is no need to
>> rush the conversion.
>>
>> The single-link chain users could be converted to the new API directly,
>> this will remove some global variables. But at first should be better to
>> gain more users who actually need the chained power off since they may
>> have very specific requirements not covered by the current variant of
>> the API and will be easier to evolve API with less users.
> 
> All above in one or another form should be in cover letter.

Alright, apparently I overestimated a tad awareness about the current
status. I'll extend the cover letter next time, thanks.