Hi! We're running Linux 2.6.27 with i2c tools 3.0.2. We have a number of userspace program using the raw i2c_smbus interface to talk to a variety of devices. Right now, it seems like every program can open up the device and issue commands, which interferes with an already running command. I see the code in open_i2c_bus using: sprintf(filename, "/dev/i2c/%d", i2cbus); file = open(filename, O_RDWR); Would adding O_EXCL to this open help to make things exclusive? Or is there a better way to do what I want. Right now we're going to set up a daemon to arbitrate access to the I2C bus, but it would be nice if we had something simpler, since now all apps have to talk to the daemon. I was thinking something along the lines of just telling userspace to loop opening the device exclusively until that succeeds, run the command, then close the device. Thanks, Pete -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html