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From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Kent Gibson <warthog618@gmail.com>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-gpio <linux-gpio@vger.kernel.org>,
	Linus Walleij <linus.walleij@linaro.org>
Subject: Re: [PATCH v4 00/20] gpio: cdev: add uAPI v2
Date: Mon, 17 Aug 2020 21:25:30 +0200	[thread overview]
Message-ID: <CAMpxmJV6k=mQaYsH_abTHhyXis+hLJkJX+M9jAtciUB=0uoEUA@mail.gmail.com> (raw)
In-Reply-To: <20200817184018.GV1891694@smile.fi.intel.com>

On Mon, Aug 17, 2020 at 8:40 PM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> On Mon, Aug 17, 2020 at 08:24:24PM +0200, Bartosz Golaszewski wrote:
> > On Fri, Aug 14, 2020 at 5:03 AM Kent Gibson <warthog618@gmail.com> wrote:
> > >
> > > This patchset defines and implements adds a new version of the
> > > GPIO CDEV uAPI to address existing 32/64-bit alignment issues, add
> > > support for debounce, event sequence numbers, and allowing for requested
> > > lines with different configurations.
> > > It provides some future proofing by adding optional configuration fields
> > > and padding reserved for future use.
> > >
> > > The series can be partitioned into two sets; the first eleven
> > > contain the v2 uAPI implementation, and the final seven port
> > > the GPIO tools to the v2 uAPI and extend them to use new uAPI features.
> > >
> > > The more complicated patches include their own commentary where
> > > appropriate.
>
> > The series looks quite good to me and I think we're on track to get it
> > in for v5.10. I'd love to have Andy (Cc'd) take a look as well. There
> > are some nits here and there but as long as we get the ABI right, any
> > implementation details can be ironed out later.
> >
> > I need to think about some details a bit more but I really like the
> > current state of the patches.
>
> First of all, I apologize for being silent, I'm quite busy with internal
> development / work.
>
> Second, I didn't hear further why we can't fix current ABI as proposed by Arnd
> and see what we will have afterwards?
>

Sure we can get back to fixing it but it will only address a single
bug and still not allow us to add new features and simplifications. Do
you mind rebasing your old patch on top of v5.9-rc1?

> Third, I'm not satisfied with the approach of wasting some memory for padding
> and I think the proper solution for the ABI is to have versioning inside the
> structures.
>
> What do you think?
>

Wasting a bit of memory is fine with me. As long as we're not copying
more than a page-worth of memory between the kernel and user-space,
the overhead is insignificant.

I prefer to make structs extensible over adding new versions in the future.

Bart

      reply	other threads:[~2020-08-17 19:26 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-14  3:02 [PATCH v4 00/20] gpio: cdev: add uAPI v2 Kent Gibson
2020-08-14  3:02 ` [PATCH v4 01/20] gpiolib: cdev: desc_to_lineinfo should set info offset Kent Gibson
2020-08-14  3:02 ` [PATCH v4 02/20] gpiolib: cdev: replace strncpy with strscpy Kent Gibson
2020-08-14  3:02 ` [PATCH v4 03/20] gpio: uapi: define GPIO_MAX_NAME_SIZE for array sizes Kent Gibson
2020-08-14  3:02 ` [PATCH v4 04/20] gpio: uapi: define uAPI v2 Kent Gibson
2020-08-14  3:02 ` [PATCH v4 05/20] gpiolib: make cdev a build option Kent Gibson
2020-08-14  3:02 ` [PATCH v4 06/20] gpiolib: add build option for CDEV v1 ABI Kent Gibson
2020-08-14  3:02 ` [PATCH v4 07/20] gpiolib: cdev: support GPIO_V2_GET_LINE_IOCTL and GPIO_V2_LINE_GET_VALUES_IOCTL Kent Gibson
2020-08-14 19:31   ` Bartosz Golaszewski
2020-08-15  6:53     ` Kent Gibson
2020-08-15  7:21       ` Bartosz Golaszewski
2020-08-15 13:21         ` Kent Gibson
2020-08-16 12:13           ` Bartosz Golaszewski
2020-08-14  3:02 ` [PATCH v4 08/20] gpiolib: cdev: support GPIO_V2_GET_LINEINFO_IOCTL and GPIO_V2_GET_LINEINFO_WATCH_IOCTL Kent Gibson
2020-08-16 12:03   ` Bartosz Golaszewski
2020-08-14  3:02 ` [PATCH v4 09/20] gpiolib: cdev: support edge detection for uAPI v2 Kent Gibson
2020-08-16 14:32   ` Bartosz Golaszewski
2020-08-18 14:00     ` Kent Gibson
2020-08-14  3:02 ` [PATCH v4 10/20] gpiolib: cdev: support GPIO_V2_LINE_SET_CONFIG_IOCTL Kent Gibson
2020-08-16 14:40   ` Bartosz Golaszewski
2020-08-14  3:02 ` [PATCH v4 11/20] gpiolib: cdev: support GPIO_V2_LINE_SET_VALUES_IOCTL Kent Gibson
2020-08-16 14:57   ` Bartosz Golaszewski
2020-08-14  3:02 ` [PATCH v4 12/20] gpiolib: cdev: support setting debounce Kent Gibson
2020-08-17 18:21   ` Bartosz Golaszewski
2020-08-18 14:37     ` Kent Gibson
2020-08-14  3:02 ` [PATCH v4 13/20] gpio: uapi: document uAPI v1 as deprecated Kent Gibson
2020-08-14  3:02 ` [PATCH v4 14/20] tools: gpio: port lsgpio to v2 uAPI Kent Gibson
2020-08-14  3:02 ` [PATCH v4 15/20] tools: gpio: port gpio-watch " Kent Gibson
2020-08-14  3:02 ` [PATCH v4 16/20] tools: gpio: rename nlines to num_lines Kent Gibson
2020-08-14  3:02 ` [PATCH v4 17/20] tools: gpio: port gpio-hammer to v2 uAPI Kent Gibson
2020-08-14  3:02 ` [PATCH v4 18/20] tools: gpio: port gpio-event-mon " Kent Gibson
2020-08-14  3:02 ` [PATCH v4 19/20] tools: gpio: add multi-line monitoring to gpio-event-mon Kent Gibson
2020-08-14  3:02 ` [PATCH v4 20/20] tools: gpio: add debounce support " Kent Gibson
2020-08-17 18:24 ` [PATCH v4 00/20] gpio: cdev: add uAPI v2 Bartosz Golaszewski
2020-08-17 18:40   ` Andy Shevchenko
2020-08-17 19:25     ` Bartosz Golaszewski [this message]

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