Experimental Physics and
Industrial Control System

Rod Nussbaumer <[email protected]> · Sat, 11 May 2013 08:23:17 -0700

Sebastion:

Since you say 'accessed as root' I will assume your OS is Linux. You

haven't said what GPIB hardware (hence, what driver) you're using. Quite

possibly, there is no need to develop device support. If your hardware

is compatible with NI hardware or otherwise supported by the open source

Linux GPIB drivers, then using those in conjunction with Asyn &

StreamDevice is likely to be a recipe for success, especially if the

power supply uses a SCPI style language. The only code you'll have to

write doing this will be a protocol file that defines how EPICS records

send and receive string data. Just using asyn (and asynRecord; highly

under-appreciated) adds a great deal of value to the system and

contributes greatly to the development process.

Rod Nussbaumer
ISAC Controls, TR|IUMF
Vancouver, Canada

Sebastian Matkovich wrote:

hey, does this kernel message say you anything? kernel: gpib: need to

hold board lock to perform ioctl; i found the sourcecode writing this:

if( current->pid != board->locking_pid )

{
printk( "gpib: need to hold board lock to perform ioctl %i\n",
cmd & 0xff );
retval = -EPERM;
goto done;
}

what i try is to build device support for a powersupply connected

through a gpib interface.

someone told me it might be because two different processes try to

access the board, or maybe it isn't accessed by root (but i executed

the ioc as root), has anyone got an idea?^^

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System