linux: Add note about esptun baudrates

This commit is contained in:
Wladimir J. van der Laan 2020-02-22 15:01:08 +00:00
parent 0ebae26c05
commit a241403058

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@ -27,6 +27,18 @@ For example:
(setting the MTU to `1500-20-8` the typical network MTU minus IP and UDP header overhead, because (setting the MTU to `1500-20-8` the typical network MTU minus IP and UDP header overhead, because
otherwise the ESP's network stack will drop the oversized packets) otherwise the ESP's network stack will drop the oversized packets)
### Baudrate note
If the tunnel hangs intermittently, the problem may be the `BAUDRATE` setting. The ESP8285 can handle
baudrates up to `115200*40 = 4608000` baud and `esptun` will try switching to a higher baudrate.
However, these higher baudrates are unstable as it seems that the UART cannot
keep up reading in some cases and loses data. This may be a misconfiguration or something that could
be improved in the `8250_dw` Linux driver for this peripheral (DMA support?).
Which values work may vary, if you want to be completely safe use `115200`. The value can be changed
at the top of `esptun.c`.
Host side Host side
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