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Date:   Sun, 5 Nov 2023 09:12:34 +0800
From:   Kent Gibson <warthog618@gmail.com>
To:     Linus Walleij <linus.walleij@linaro.org>
Cc:     Bartosz Golaszewski <brgl@bgdev.pl>,
        Andy Shevchenko <andy@kernel.org>, linux-gpio@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] RFC: Do not enable the v1 uAPI by default
Message-ID: <ZUbsAhXyk-d4R2M9@rigel>
References: <20231104-no-y-uapi1-default-v1-1-f60d318b6fbe@linaro.org>
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On Sat, Nov 04, 2023 at 11:54:40PM +0100, Linus Walleij wrote:
> It's been two years since we introduced the v2 uAPI and
> the major consumer libgpiod is at v2.1.
>

Believe it or not, it is nearly three years.  But libgpiod support for
it, added in v2.x, is less than one year old, and migrating from libgpiod
v1 to v2 is non-trivial as their APIs are very different.
So I would not be surprised to find that the major consumer of the uAPI
remains users of libgpiod v1.x - which requires the old uAPI.

> What about discouraging the old uAPI?
>

If you want to provide the end user with two years to migrate, and given
that libgpiod is the major consumer, you might want to hold off for
another year.

OTOH, if distros/users want to continue including/using libgpiod v1 they
can always re-enable GPIO_CDEV_V1, so I'm not completely against the idea
- just be aware that it may be more disruptive than you might expect.

Cheers,
Kent.