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pinMode PWM: Unable to do this when using /dev/gpiomem. Try sudo? [message #1852166]

Tue, 03 May 2022 10:15

Kurt Struevy

Messages: 45
Registered: May 2016

Member

Hello,
since several weeks I try to find any solution for my problem.
I created an application using eclipse 2022-03 CDT. It works perfect!
a big compliment to the designers of eclipse.
After some time I got eclips running on a Windows machine using a toolchain for a raspberry pi.
Debugging for remote application works perfect.
But when I try to run an application where I use wiringpi then I get a problem where I havn't find any solution at all.
I use this code :

	pinMode(motor_l_u, OUTPUT);
	pinMode(motor_l_v, OUTPUT);
	pinMode(motor_r_u, OUTPUT);
	pinMode(motor_r_v, OUTPUT);
       .....
	pinMode(motor_l_u, PWM_OUTPUT);
	pinMode(motor_l_v, PWM_OUTPUT);
	pinMode(motor_r_u, PWM_OUTPUT);
	pinMode(motor_r_v, PWM_OUTPUT);

Executing the first lines makes no problem.
But when I to try execute the lines

	pinMode(motor_l_u, PWM_OUTPUT);
	pinMode(motor_l_v, PWM_OUTPUT);
	pinMode(motor_r_u, PWM_OUTPUT);
	pinMode(motor_r_v, PWM_OUTPUT);

I get this error:
pinMode PWM: Unable to do this when using /dev/gpiomem. Try sudo?
Child exited with status 1
logout
Sometimes I think there is no way to debug such a programm when it needs wiringPi.
When I run the application on a console as normal user I get the same error.
When I run this application on a console typing

 sudo MyApp

then it works.
Is there really no solution available?
I'm almost very frustrated because eclipse is a wonderfull IDE but without debugging such an appliation it's not usefull.
Kurt

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Re: pinMode PWM: Unable to do this when using /dev/gpiomem. Try sudo? [message #1852173 is a reply to message #1852166]

Tue, 03 May 2022 14:41

Tauno Voipio

Messages: 742
Registered: August 2014

Senior Member

You have to add your user to gpio group, then log out and log in again.

--

Tauno Voipio

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Re: pinMode PWM: Unable to do this when using /dev/gpiomem. Try sudo? [message #1852174 is a reply to message #1852173]

Tue, 03 May 2022 16:01

Kurt Struevy

Messages: 45
Registered: May 2016

Member

Hallo Tauno Voibio,
thanks for your quick replay!
No it's not necessary to

add your user to gpio group

I found a working solution:

create a script (e.G.: gdbscript) on the raspberry with the content
```
#! /bin/bash
#
sudo gdbserver $*
```
store it
mak it executable
```
chmod +x gdbscript
```
on eclipse modify
1. tab: -->Debugger
2. tab: ----> Gdbserver Settings
3. tab ------> in Gdbserver path write:
```
/home/raspi/gdbscript
```

the result is:

Last login: Tue May  3 18:08:32 2022 from 192.168.180.38

/home/raspi/gdbscript  :2345 /home/raspi/Eclipse/RoboCar;exit

raspi@raspberrypi:~$ /home/raspi/gdbscript  :2345 /home/raspi/Eclipse/RoboCar;exit
Process /home/raspi/Eclipse/RoboCar created; pid = 4686
Listening on port 2345
Remote debugging from host 192.168.180.38

see attached picture
that should work.

Attachment: NeuerDebuggerGdbserver path.PNG
(Size: 45.95KB, Downloaded 116 times)

[Updated on: Tue, 03 May 2022 16:23]

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Re: pinMode PWM: Unable to do this when using /dev/gpiomem. Try sudo? [message #1852176 is a reply to message #1852174]

Tue, 03 May 2022 16:43

Tauno Voipio

Messages: 742
Registered: August 2014

Senior Member

Your solution is to run the target as root, which is not secure. Adding the user to the gpio group is sufficient for running wiringPi, so the target code does not have other unnecessary superuser powers.

--

Tauno Voipio

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Re: pinMode PWM: Unable to do this when using /dev/gpiomem. Try sudo? [message #1852193 is a reply to message #1852176]

Wed, 04 May 2022 13:40

Kurt Struevy

Messages: 45
Registered: May 2016

Member

Hi Tauno Voipio,
thanks for your answer.
Yes I did it but it doesn't work.

raspi@raspberrypi:~ $ sudo adduser raspi gpio
The user `raspi' is already a member of `gpio'.
raspi@raspberrypi:~ $ cd Eclipse/
raspi@raspberrypi:~/Eclipse $ ./RoboCar
Hello World

init Wiringppi !!

init ist OK!!
+++++++++++++
pinMode PWM: Unable to do this when using /dev/gpiomem. Try sudo?

I think it's not a real security problem if I do it with my private application which runs only on a restricted area.
Kurt

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Re: pinMode PWM: Unable to do this when using /dev/gpiomem. Try sudo? [message #1852203 is a reply to message #1852193]

Wed, 04 May 2022 18:26

Tauno Voipio

Messages: 742
Registered: August 2014

Senior Member

What does ls -l /dev/gpiomem show?

--

Tauno Voipio

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Re: pinMode PWM: Unable to do this when using /dev/gpiomem. Try sudo? [message #1852221 is a reply to message #1852203]

Thu, 05 May 2022 08:57

Kurt Struevy

Messages: 45
Registered: May 2016

Member

Hi Tauno Voipio,
the output shows:

ls -la /dev/gpiomem
crw-rw---- 1 root gpio 246, 0 May  4 18:17 /dev/gpiomem

[Updated on: Thu, 05 May 2022 08:59]

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Re: pinMode PWM: Unable to do this when using /dev/gpiomem. Try sudo? [message #1852222 is a reply to message #1852221]

Thu, 05 May 2022 08:57

Kurt Struevy

Messages: 45
Registered: May 2016

Member

No Message Body

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Re: pinMode PWM: Unable to do this when using /dev/gpiomem. Try sudo? [message #1852238 is a reply to message #1852221]

Thu, 05 May 2022 16:01

Tauno Voipio

Messages: 742
Registered: August 2014

Senior Member

That seems fine.

Can you run the test binary from Raspberry console?

Are you sure that the target binary is owned by the user in gpio group?

I did run a wiringPi test on my Raspberry 3b and it runs fine.

--

Tauno Voipio

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Re: pinMode PWM: Unable to do this when using /dev/gpiomem. Try sudo? [message #1852255 is a reply to message #1852238]

Fri, 06 May 2022 09:34

Kurt Struevy

Messages: 45
Registered: May 2016

Member

Hi Tauno Voipio,
yes I checked this.

raspi@raspberrypi:~/Eclipse $ groups raspi
raspi : raspi adm dialout cdrom sudo audio video plugdev games users input netdev spi i2c gpio lpadmin
raspi@raspberrypi:~/Eclipse $ ./TestMotorProgramm
pinMode PWM: Unable to do this when using /dev/gpiomem. Try sudo?
raspi@raspberrypi:~/Eclipse $ sudo ./TestMotorProgramm
====> Vorwaerts mit Tempo =1023
====> Vorwaerts mit Tempo =1022

I use this image

Linux raspberrypi 5.10.17+ #1414 Fri Apr 30 13:16:27 BST 2021 armv6l GNU/Linux

Isn't it crazy?

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Re: pinMode PWM: Unable to do this when using /dev/gpiomem. Try sudo? [message #1852422 is a reply to message #1852255]

Mon, 16 May 2022 07:04

Emmanuel Torres

Messages: 1
Registered: May 2022

Junior Member

Hi Kurt,

I am facing the same issue! Did you find a solution??

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Re: pinMode PWM: Unable to do this when using /dev/gpiomem. Try sudo? [message #1852537 is a reply to message #1852422]

Sun, 22 May 2022 10:36

Kurt Struevy

Messages: 45
Registered: May 2016

Member

No Message Body

[Updated on: Sun, 22 May 2022 10:39]

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Re: pinMode PWM: Unable to do this when using /dev/gpiomem. Try sudo? [message #1852538 is a reply to message #1852537]

Sun, 22 May 2022 10:38

Kurt Struevy

Messages: 45
Registered: May 2016

Member

Hi Emmanuel Torres
No this is the only solution which I found.

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Re: pinMode PWM: Unable to do this when using /dev/gpiomem. Try sudo? [message #1853042 is a reply to message #1852166]

Wed, 15 June 2022 15:37

Johnny Bravo

Messages: 2
Registered: June 2022
Location: United States

Junior Member

Same issue... Can't find the solution. If you come across anything, please mention it here.

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