Actually no, I changed its file attributes to 644, but it still popped up the same message as a normal user.
Looks like for hp-toolbox, hp-info and /usr/lib/cups/backend/hp I require root priviledges:
$ sudo /usr/lib/cups/backend/hp
direct hp:/usb/HP_LaserJet_P1006?serial=AC094VM "HP LaserJet P1006" "HP LaserJet P1006 USB AC094VM HPLIP" "MFG:HP;MDL:HP LaserJet P1006;CLS:PRINTER;DES:HP LaserJet P1006;SN:AC094VM;"
Actually no, I changed its file attributes to 644, but it still popped up the same message as a normal user. cups/backend/ hp I require root priviledges:
Looks like for hp-toolbox, hp-info and /usr/lib/
$ sudo /usr/lib/ cups/backend/ hp HP_LaserJet_ P1006?serial= AC094VM "HP LaserJet P1006" "HP LaserJet P1006 USB AC094VM HPLIP" "MFG:HP;MDL:HP LaserJet P1006;CLS: PRINTER; DES:HP LaserJet P1006;SN:AC094VM;"
direct hp:/usb/