Messages in this thread | | | Date | Tue, 26 Sep 2017 00:05:16 +0100 | From | Alan Cox <> | Subject | Re: RFC: mcu_tty: Trying to open /dev/ttyUSB0 and lock access from a kernel driver |
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On Mon, 25 Sep 2017 15:01:13 +0200 Ulf Samuelsson <linux-kernel@emagii.com> wrote:
> Trying to open /dev/ttyUSB from a kernel driver (which works), but > locking the > serial port so noone else can access it does not work. > Any advice would be appreciated.
File locks are advisory only.
For the rest of it you might want to take a look at how the gsm mux driver works (the protocol stuff is scary but you can ignore that end). It plugs a line discipline into a tty and that muxes out as a collection of ttys and shows how it's meant to be done.
That also means you have an owning process with the port open that can do locking on it and/or route any raw read/writes to the master port into the bit bucket.
Alan
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