On Sun, Mar 3, 2019 at 6:00 AM Greg KH <greg@xxxxxxxxx> wrote: > > On Sun, Mar 03, 2019 at 03:55:44AM -0500, Jeffrey Walton wrote: > > ... > > Again, go delete modem manager off of your system, it is the thing that > keeps opening the port up to see if you have made a valid connection on > the device or not. If you write your own program to talk to the device, > modem manager is not needed at all, and is known to cause this problem. Thanks Greg. I deleted modem manager, then ran two instances of my program. Both opened the device with O_EXCL, and both opens succeeded. They proceeded to much with one another's state. I don't think modem manager is the problem here. The first problem is the way this device is setup. An exclusive resource is being treated as a shared resource. The second problem is open silently ignores flags. Epic fail. Thanks again for the help. Jeff _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
