On Sun, Mar 3, 2019 at 12:55 AM <valdis.kletnieks@xxxxxx> wrote: > > On Sat, 02 Mar 2019 14:36:12 -0500, Jeffrey Walton said: > > > I feel like I am missing something... Does Linux consider the modem a > > shared resource instead of an exclusive resource? What use cases > > support two different programs sending commands to the modem at the > > same time? > > The Linux kernel has exactly zero clue what a "modem" is. It's talking to a > serial port, and doesn't care where the other end of the serial cable is. If > you have a onboard modem, that cable may be all of 2 mm long and consist of a > bunch of traces between two chips on a PCB, or even internal connections > between two sides of a chip, but it's still there. > > So the correct question is "what use cases have two programs talking to the > same serial port"? I agree about the general case of serial lines and /dev/ttySn. However... /dev/ttyACMn are modems, not serial lines. For whatever reason the kernel made a special case for the devices. The kernel knows exactly what they are. Jeff _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
