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From: Bartosz Golaszewski <brgl@bgdev.pl>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com>,
	Kent Gibson <warthog618@gmail.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 10/11] gpiolib: add new ioctl() for monitoring changes in line info
Date: Thu, 19 Dec 2019 14:05:19 +0100	[thread overview]
Message-ID: <CAMRc=Mcy=Q+9Eb6mb5JEq+CCbxgBY1CfTDsYj1Rt9bcLXgeY=g@mail.gmail.com> (raw)
In-Reply-To: <CAHp75VfeEB5RudwMaoiMTMMY3zW-kz-h=rJ3Cu5_tyRL6ZuF1w@mail.gmail.com>

wt., 10 gru 2019 o 18:00 Andy Shevchenko <andy.shevchenko@gmail.com> napisał(a):
>
> > On a different note: why would endianness be an issue here? 32-bit
> > variables with 64-bit alignment should still be in the same place in
> > memory, right?
>
> With explicit padding, yes.
>
> > Any reason not to use __packed for this structure and not deal with
> > this whole compat mess?
>
> Have been suggested that explicit padding is better approach.
> (See my answer to Kent)
>
> > I also noticed that my change will only allow user-space to read one
> > event at a time which seems to be a regression with regard to the
> > current implementation. I probably need to address this too.
>
> Yes, but we have to have ABI v2 in place.

Hi Andy,

I was playing with some ideas for the new ABI and noticed that on
64-bit architecture the size of struct gpiochip_info is reported to be
68 bytes, not 72 as I would expect. Is implicit alignment padding not
applied to a struct if there's a non-64bit-aligned 32-bit field at the
end of it? Is there something I'm missing here?

Bart

  reply	other threads:[~2019-12-19 13:05 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-04 15:59 [PATCH v2 10/11] gpiolib: add new ioctl() for monitoring changes in line info Bartosz Golaszewski
2019-12-04 15:59 ` [PATCH v2 11/11] tools: gpio: implement gpio-watch Bartosz Golaszewski
2019-12-04 22:42   ` Andy Shevchenko
2019-12-05  9:45     ` Bartosz Golaszewski
2019-12-05  9:44   ` Kent Gibson
2019-12-05  9:48     ` Bartosz Golaszewski
2019-12-04 22:34 ` [PATCH v2 10/11] gpiolib: add new ioctl() for monitoring changes in line info Andy Shevchenko
2019-12-05  9:42   ` Bartosz Golaszewski
2019-12-05 10:27     ` Andy Shevchenko
2019-12-05 13:47       ` Bartosz Golaszewski
2019-12-05 17:02         ` Andy Shevchenko
2019-12-06 21:20           ` Bartosz Golaszewski
2019-12-10 17:00             ` Andy Shevchenko
2019-12-19 13:05               ` Bartosz Golaszewski [this message]
2019-12-19 13:12                 ` Kent Gibson
2019-12-19 13:17                   ` Bartosz Golaszewski
2019-12-05 10:47 ` Kent Gibson
2019-12-05 10:50   ` Bartosz Golaszewski

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