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From: Pedro Botella <pbotella@gmail.com>
To: linux-gpio@vger.kernel.org
Subject: [libgpiod] Bug in python binding when requesting output?
Date: Thu, 11 Feb 2021 21:54:22 +0100	[thread overview]
Message-ID: <CAJAEvhib-M-UQeoCDs+aex-hdE-vJSQk=C5B7z4A9WmR+JcxQQ@mail.gmail.com> (raw)

Hi,

I'm experiencing what I think is a bug in the python bindings for libgpiod.
I believe a line.request with type gpiod.LINE_REQ_DIR_OUT always
results in that line being set to '0'.
To reproduce:
1. request a line with type gpiod.LINE_REQ_DIR_OUT
2. set the line to '1'
3. release the line
4. request the same line with type gpiod.LINE_REQ_DIR_OUT
5. get the value, it should now be '0'

I think the issue is in "gpiod_LineBulk_request" in
https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git/tree/bindings/python/gpiodmodule.c
There a call to "gpiod_line_request_bulk" with default_vals being
passed as a pointer. Later on in the code, this parameter is checked
for NULL, if it is not NULL then the values in the array are used as
default_vals.
I believe that a NULL pointer should be passed instead if no
default_vals have been requested when doing a Line.request from
Python.

BR
Pedro

             reply	other threads:[~2021-02-11 20:55 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-11 20:54 Pedro Botella [this message]
2021-02-13  0:23 ` [libgpiod] Bug in python binding when requesting output? Kent Gibson
2021-02-15  8:15   ` Pedro Botella
2021-02-15  9:11     ` Kent Gibson
2021-02-15 11:33       ` Pedro Botella

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