** Also affects: linux-raspi (Ubuntu Focal)
Importance: Undecided
Status: New
** Changed in: linux-raspi (Ubuntu)
Status: New => Invalid
** Changed in: linux-raspi (Ubuntu Focal)
Status: New => Triaged
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https://bugs.launchpad.net/bugs/1889926
Title:
Can't access gpio mapped memory on focal armhf server on pi
Status in linux-raspi package in Ubuntu:
Invalid
Status in linux-raspi source package in Focal:
Triaged
Bug description:
On released (and apt updated) 20.04 armhf preinstalled server on
Pi3B+, we cannot use pigpio C program to access memory map for gpio.
Customer says the same code works fine on 18.04.
ubuntu@ubuntu:~$ sudo ./pigpio/kyle.o
2020-07-31 18:36:11 initPeripherals: mmap gpio failed (Operation not
permitted)
Details on code below, but the executable is attached, and the
customer says this fairly represents their code usage.
ubuntu@ubuntu:~/pigpio$ uname -a
Linux ubuntu 5.4.0-1015-raspi #15-Ubuntu SMP Fri Jul 10 05:37:25 UTC 2020
armv7l armv7l armv7l GNU/Linux
We thought perhaps these kernel configs were involved:
CONFIG_DEVMEM=y
CONFIG_ARCH_HAS_DEVMEM_IS_ALLOWED=y
CONFIG_STRICT_DEVMEM=y
... and we modified the kernel cmdline with the following, but the result was
the same.
iomem=relaxed strict-devmem=0
The program is simply this https://github.com/joan2937/pigpio/ with make &
make install
then this c file:
#include <pigpio.h>
#include <stdio.h>
#include <stdlib.h>
int main(void){
gpioInitialise();
}
built with gcc -Wall -I/home/ubuntu/pigpio -pthread -o kyle.o kyle.c
-lpigpio -lrt
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