Re: [PATCH] gpio: Revert regression in sysfs-gpio (gpiolib.c) #forregzbot

[Thorsten Leemhuis <regressions@leemhuis.info>]

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#regzbot fixed-by: fc328a7d1fcce263db0b046917a66f3aa6e68719
#regzbot monitor:
https://lore.kernel.org/lkml/20220314192522.GA3031157@roeck-us.net/

On 07.03.22 11:12, Thorsten Leemhuis wrote:
> On 07.03.22 10:58, Bartosz Golaszewski wrote:
>> On Fri, Mar 4, 2022 at 8:13 AM Thorsten Leemhuis
>> <regressions@leemhuis.info> wrote:
>>> On 16.02.22 15:40, Bartosz Golaszewski wrote:
>>>> On Tue, Feb 15, 2022 at 10:56 PM Linus Walleij <linus.walleij@linaro.org> wrote:
>>>>>
>>>>> On Mon, Feb 14, 2022 at 12:24 AM Marcelo Roberto Jimenez
>>>>> <marcelo.jimenez@gmail.com> wrote:
>>>>>> On Sat, Feb 12, 2022 at 1:55 PM Linus Walleij <linus.walleij@linaro.org> wrote:
>>>>>
>>>>>>> I am curious about the usecases and how deeply you have built
>>>>>>> yourselves into this.
>>>>>>
>>>>>> I don't know if I understand what you mean, sorry.
>>>>>
>>>>> Why does the user need the sysfs ABI? What is it used for?
>>>>>
>>>>> I.e what is the actual use case?
>>>>>
>>>>>>>> In any case, the upstream file should be enough to test the issue reported here.
>>>>>>>
>>>>>>> The thing is that upstream isn't super happy that you have been
>>>>>>> making yourselves dependent on features that we are actively
>>>>>>> discouraging and then demanding that we support these features.
>>>>>>
>>>>>> Hum, demanding seems to be a strong word for what I am doing here.
>>>>>>
>>>>>> Deprecated should not mean broken. My point is: the API seems to be
>>>>>> currently broken. User space apps got broken, that's a fact. I even
>>>>>> took the time to bisect the kernel and show you which commit broke it.
>>>>>> So, no, I am not demanding. More like reporting and providing a
>>>>>> temporary solution to those with a similar problem.
>>>>>>
>>>>>> Maybe it is time to remove the API, but this is up to "upstream".
>>>>>> Leaving the API broken seems pointless and unproductive.
>>>>>>
>>>>>> Sorry for the "not super happiness of upstream", but maybe upstream
>>>>>> got me wrong.
>>>>>>
>>>>>> We are not "making ourselves dependent on features ...". The API was
>>>>>> there. We used it. Now it is deprecated, ok, we should move on. I got
>>>>>> the message.
>>>>>
>>>>> Ouch I deserved some slamming for this.
>>>>>
>>>>> I'm sorry if I came across as harsh :(
>>>>>
>>>>> I just don't know how to properly push for this.
>>>>>
>>>>> I have even pushed the option of the deprecated sysfs ABI
>>>>> behind the CONFIG_EXPERT option, which should mean that
>>>>> the kernel config has been made by someone who has checked
>>>>> the option "yes I am an expert I know what I am doing"
>>>>> yet failed to observe that this ABI is obsoleted since 5 years
>>>>> and hence failed to be an expert.
>>>>>
>>>>> Of course the ABI (not API really) needs to be fixed if we can find the
>>>>> problem. It's frustrating that fixing it seems to fix broken other
>>>>> features which are not deprecated, hence the annoyance on my
>>>>> part.
>>>>>
>>>>
>>>> I'm afraid we'll earn ourselves a good old LinusRant if we keep
>>>> pushing the character device as a solution to the problem here.
>>>> Marcelo is right after all: he used an existing user interface, the
>>>> interface broke, it must be fixed.
>>>>
>>>> I would prefer to find a solution that fixes Marcelo's issue while
>>>> keeping the offending patches in tree but it seems like the issue is
>>>> more complicated and will require some rework of the sysfs interface.
>>>>
>>>> In which case unless there are objections I lean towards reverting the
>>>> relevant commits.
>>>
>>> Sounds good to me, but that was two weeks ago and afaics nothing
>>> happened since then. Or did the discussion continue somewhere else?
>>
>> Now queued for fixes, thanks for the reminder.
> 
> thx, and yw, that's what I'm here for ;-)
> 
> Sadly that commit didn't use 'Link:' tags pointing to the report (the
> start of this thread) using lore.kernel.org/r/, as explained in
> 'Documentation/process/submitting-patches.rst' and
> 'Documentation/process/5.Posting.rst'. I'd say that would have been
> really wise here if someone sooner or later needs to look into the
> backstory of the fix. And is also means that I have to tell my
> regression tracking bot about this issue manually now. :-/
> 
> #regzbot fixed-by: 86528d306d1826cfe59481001d63761ba793317a
> 
> But whatever, thx for taking care of this!
> 
> Have a nice week everyone!
> 
> Ciao, Thorsten
> 
>>>>>> And I will also tell the dev team that they must use the GPIO char dev
>>>>>> and libgpiod from now on and must port everything to it. And we will
>>>>>> likely have another group of people who are not super happy, but
>>>>>> that's life... :)
>>>>>
>>>>> I'm happy to hear this!
>>>
>>> Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
>>>
>>> P.S.: As the Linux kernel's regression tracker I'm getting a lot of
>>> reports on my table. I can only look briefly into most of them and lack
>>> knowledge about most of the areas they concern. I thus unfortunately
>>> will sometimes get things wrong or miss something important. I hope
>>> that's not the case here; if you think it is, don't hesitate to tell me
>>> in a public reply, it's in everyone's interest to set the public record
>>> straight.
>>>
>>> #regzbot poke
>>