23

I am working on writing a graphical application that uses the Pi's GPU, and I constantly get * failed to open vchiq instance errors when running my programs. This is usually fixed by a sudo chmod 777 /dev/vchiq, but (1) this is a very insecure fix that is definitely not suited to deployment to user-owned devices, and (2) it gets reset after each reboot.

How can I fix my /dev/vchiq problems "the right way", persistently, without introducing security issues?

fouric
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5 Answers5

32

I was able to solve a similar problem by adding myself to the video group (I was not using the default user). Maybe this can help.

The command is:

sudo usermod -a -G video $(whoami)

You will need to log out and in again for the change to take effect.

Mickaël
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9

You can create a udev rule to set specific permissions on the device. As root, you could:

echo 'SUBSYSTEM=="vchiq",GROUP="video",MODE="0660"' > /etc/udev/rules.d/10-vchiq-permissions.rules
usermod -a -G video YourUnprivilegedUser
Nicolas Dufresne
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5

You could set SUID permission

sudo chmod u+s /dev/vchiq
SlySven
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Milliways
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3

If you are running raspistill from a php script accessed via a browser then you need to enter: sudo usermod -a -G video www-data to give Apache the necessary permissions.

mirams
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C Wheatley
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0

add 

start_x=1 
gpu_mem=256

to boot/config.txt then run sudo raspistill -o cam.jpg

Of course I added the path for the raspistill. It worked for me in Ubuntu.

Jacobm001
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user40120
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