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elixir-circuits / circuits_uart

Discover and use UARTs and serial ports in Elixir
Apache License 2.0
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Possible option to set timeout on Open ? #113

Closed CharlesOkwuagwu closed 3 years ago

CharlesOkwuagwu commented 3 years ago

Setup

circuits_uart.open command has no way to configure a timeout, the default 4000ms always applies, and the error below might be avoidable if we could configure a longer or flexible timeout say.

** (stop) :port_timed_out
    (circuits_uart 1.4.3) lib/circuits_uart.ex:563: Circuits.UART.call_port/4
    (circuits_uart 1.4.3) lib/circuits_uart.ex:359: Circuits.UART.handle_call/3
    (stdlib 3.16.1) gen_server.erl:721: :gen_server.try_handle_call/4
    (stdlib 3.16.1) gen_server.erl:750: :gen_server.handle_msg/6
    (stdlib 3.16.1) proc_lib.erl:226: :proc_lib.init_p_do_apply/3

https://github.com/elixir-circuits/circuits_uart/blob/7181819bfce930de2c51c6b8a0991d1d4a461892/lib/circuits_uart.ex#L552

Provision to supply a timeout to call_port is not given from open.

Was that intentional?

fhunleth commented 3 years ago

Hi @CharlesOkwuagwu!

Regarding whether this was intentional or not, I don't recall having open take so long before either working or returning an error. Since I don't work hardly at all on Windows these days, it might be a new behavior with dealing with some serial ports.

In any case, I certainly wouldn't oppose having a settable timeout on open. I just wonder if something else is happening and perhaps an error should be detected and returned earlier. Do you have any idea why the open is taking so long on your system?

CharlesOkwuagwu commented 3 years ago

I see this happen mainly on application restarts when maybe the modem had been in use prior and is just re-initializing itself.

What I then do is delay 30 seconds then retry the open, which always works.