[Solved] Shutdown with Power Button on Pi5

[Rabie]

Hi,

How can I get the Pi 5 to run the command "sudo poweroff" when I press the power button? Thanks in advance

[Rabie]

okay I made a C Skript and compiled it, then i put it in bootlocal.sh and it worked.
The Topic is now solved.
Sorry for not trying alone before.

Code: [Select]

cat /opt/Scripts/psw_shutdown.c
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <linux/input.h>

#define DEVICE "/dev/input/event0"

int main() {
    struct input_event ev;
    int fd = open(DEVICE, O_RDONLY);
    if (fd == -1) {
        perror("Failed to open input device");
        return 1;
    }

    printf("Listening for PSW button on %s...\n", DEVICE);

    while (1) {
        if (read(fd, &ev, sizeof(struct input_event)) == -1) {
            perror("Failed to read input event");
            close(fd);
            return 1;
        }

        if (ev.type == EV_KEY && ev.code == KEY_POWER && ev.value == 1) {
            printf("Power button pressed! Shutting down...\n");
            system("sudo poweroff");
            break;
        }
    }

    close(fd);
    return 0;
}

[Rich]

Hi Rabie
Looks good, but I suspect it may be consuming a lot of
CPU cycles. If you run  top , does it show psw_shutdown
consuming a large percentage of CPU clock cycles?

I would have done something to slow the  while() loop
down, for instance:

Code: [Select]

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <linux/input.h>

#define DEVICE "/dev/input/event0"

int main() {
    struct input_event ev;
    int fd = open(DEVICE, O_RDONLY);
    if (fd == -1) {
        perror("Failed to open input device");
        return 1;
    }

    printf("Listening for PSW button on %s...\n", DEVICE);

    while (1) {
        if (read(fd, &ev, sizeof(struct input_event)) == -1) {
            perror("Failed to read input event");
            close(fd);
            return 1;
        }

        if (ev.type == EV_KEY && ev.code == KEY_POWER && ev.value == 1) {
            printf("Power button pressed! Shutting down...\n");
            system("sudo poweroff");
            break;
        }

    usleep(250000);        // Limit polling rate to 4 times per second.

    }

    close(fd);
    return 0;
}
That would be the simplest way of taming that loop.
A more advanced way would be to monitor the  fd
using a  select()  instruction, but the  usleep()  is
quite sufficient for this application.

[Rabie]

hi Rich,

i see this

Code: [Select]

Mem: 823732K used, 7315548K free, 100576K shrd, 316K buff, 499368K cached
CPU:  0.8% usr  0.3% sys  0.0% nic 98.7% idle  0.0% io  0.0% irq  0.0% sirq
Load average: 0.05 0.12 0.09 2/162 4914

PID  PPID USER     STAT   VSZ %VSZ CPU %CPU COMMAND
3249     1 root     S     1748  0.0   0  0.0 /opt/Scripts/psw_shutdown
I am not realy a pro so I don't really understand, if thats a lot.
but I think it looks fine.
what do u think ?

[Rich]

Hi Rabie
I must admit, I am surprised. That does look fine.
Usually a loop like that will keep a CPU very busy.