Re: [PATCH 1/3] gpio: mockup: fix indicated direction

[Bartosz Golaszewski <brgl@xxxxxxxx>]

pt., 9 lis 2018 o 12:54 Uwe Kleine-König
<u.kleine-koenig@xxxxxxxxxxxxxx> napisał(a):
>
> Hello Bartosz,
>
> On Fri, Nov 09, 2018 at 12:13:44PM +0100, Bartosz Golaszewski wrote:
> > czw., 8 lis 2018 o 21:35 Uwe Kleine-König
> > <u.kleine-koenig@xxxxxxxxxxxxxx> napisał(a):
> > > On Thu, Nov 08, 2018 at 05:52:53PM +0100, Bartosz Golaszewski wrote:
> > > > Commit 3edfb7bd76bd ("gpiolib: Show correct direction from the
> > > > beginning") fixed an existing issue but broke libgpiod tests by
> > > > changing the default direction of dummy lines to output.
> > >
> > > The indicated commit only changed what was shown in debugfs, but didn't
> > > touch the actual direction of a GPIO, doesn't it? If someone called
> > > gpiod_get_direction before it would have returned "output", too, unless
> > > I miss something.
> > >
> >
> > This commit (3edfb7bd76bd) sets the correct direction of the line by
> > actually calling get_direction() instead of assuming input if
> > direction_input is not NULL. It just so happened that previously the
> > default direction of gpio-mockup lines was output but it would be
> > displayed as input due to this inconsistency.
>
> Does the test that fails since 3edfb7bd76bd use debugfs/gpio to find out
> the direction of a gpio? I'd say it's a bad idea to depend on this as
> (AFAICT) debugfs is only a debug aid and you shouldn't depend on stuff
> contained in it.
>

No, this is what we get from the LINEINFO ioctl(). I only use debugfs
for triggering dummy interrupts.

> I'd weaken the commit log a bit to not claim that the commit broke
> libgpiod but that it only made the inconsistency visible. After all this
> commit didn't "change the default direction of dummy lines to output",
> they were an output already before.
>

Well it did break the tests you know. ;)

I guess no harm in rewording the message.

Bart