Giters

jgarff / rpi_ws281x

Userspace Raspberry Pi PWM library for WS281X LEDs

Geek Repo:Geek Repo

Github PK Tool:Github PK Tool

Cannot run on Pi 4 without sudo - Can't open /dev/mem: Permission denied - Failed to setup lights driver, result code: WS2811_ERROR_MMAP

Sciss opened this issue · comments

commented

I am using the Java / JNI wrapper. I already tried some suggestions like adding user pi to group gpio, and chown and chmod on /dev/mem, this doesn't change the problem:

16:43:59.142 [main] INFO  com.github.mbelling.ws281x.Ws281xLedStrip - Native library loaded
Can't open /dev/mem: Permission denied
!! Failed to initialize WS2811:
java.lang.RuntimeException: Failed to setup lights driver, result code: WS2811_ERROR_MMAP
	at com.github.mbelling.ws281x.Ws281xLedStrip.init(Ws281xLedStrip.java:234)
	at com.github.mbelling.ws281x.Ws281xLedStrip.<init>(Ws281xLedStrip.java:98)

As my application needs to read and write user files, running it as root is not an option. Please help find a fix to this problem. Thanks

commented

You can use SPI instead of PWM. You can't use PWM without root.

commented

I see. My workaround is now to run the PWM control in a separate process that is controlled via OSC input, so only that process has to run under sudo.