From a2414030582daaa0f5412920d618a20815baaea5 Mon Sep 17 00:00:00 2001 From: "Wladimir J. van der Laan" Date: Sat, 22 Feb 2020 15:01:08 +0000 Subject: [PATCH] linux: Add note about esptun baudrates --- linux/README.md | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/linux/README.md b/linux/README.md index 5ff62e9..27ccd2f 100644 --- a/linux/README.md +++ b/linux/README.md @@ -27,6 +27,18 @@ For example: (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) +### 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 ---------