Firmware hangup in i2c_stop() and other I2C functions #3

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1. maxgerhardt

   added

   bugSomething isn't workingSomething isn't working

   needs testingAdditional testing requiredAdditional testing required

   Component: I2CRegarding the I2C componentRegarding the I2C component

   on Jun 18, 2021
2. maxgerhardt commented on Oct 2, 2021

   

   maxgerhardt

   on Oct 2, 2021

   Last edited by maxgerhardt

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   A timeout has been added in a72b50c and 51a22bf, further improvements in PR #45 #46

   a backtrace of a lockup is also e.g.

   Program received signal SIGINT, Interrupt.
   0x08001948 in i2c_byte_write (obj=0x20000104 <Wire+20>, data=<optimized out>)
       at C:\Users\Max\.platformio\packages\framework-arduinogd32\libraries\Wire\src\utility\twi.c:157
   157         while(((i2c_flag_get(obj_s->i2c, I2C_FLAG_TBE)) == RESET) &&
   (gdb) where
   #0  0x08001948 in i2c_byte_write (obj=0x20000104 <Wire+20>,
       data=<optimized out>)
       at C:\Users\Max\.platformio\packages\framework-arduinogd32\libraries\Wire\src\utility\twi.c:157
   #1  i2c_master_transmit (obj=obj@entry=0x20000104 <Wire+20>,
       address=<optimized out>, data=0x2000014c <TwoWire::_tx_buffer> "",
       length=<optimized out>, stop=1 '<error reading variable>)
       at C:\Users\Max\.platformio\packages\framework-arduinogd32\libraries\Wire\src\utility\twi.c:241
   #2  0x08001648 in TwoWire::endTransmission (this=0x200000f0 <Wire>,
       sendStop=sendStop@entry=1 '<error reading variable>)
       at C:\Users\Max\.platformio\packages\framework-arduinogd32\libraries\Wire\src\Wire.cpp:191
   #3  0x08001666 in TwoWire::endTransmission (this=<optimized out>)
       at C:\Users\Max\.platformio\packages\framework-arduinogd32\libraries\Wire\src\Wire.cpp:207
   #4  0x08002dfe in Adafruit_SSD1306::ssd1306_commandList (
       this=this@entry=0x20000084 <display>, c=<optimized out>,
       c@entry=0x8006f3a <Adafruit_SSD1306::begin(unsigned char, unsigned char, bool, bool)::init1> <error reading variable>, n=<optimized out>,
       n@entry=4 '<error reading variable>)
       at .pio\libdeps\genericGD32F303CC\Adafruit SSD1306\Adafruit_SSD1306.cpp:402
   #5  0x08002f98 in Adafruit_SSD1306::begin (
       this=this@entry=0x20000084 <display>,
       vcs=vcs@entry=2 '<error reading variable>,
       addr=addr@entry=60 '<error reading variable>, reset=reset@entry=true,
       periphBegin=periphBegin@entry=true)
       at .pio\libdeps\genericGD32F303CC\Adafruit SSD1306\Adafruit_SSD1306.cpp:537
   #6  0x08001402 in setup () at src\main.cpp:82
   #7  0x08004cd6 in main ()
       at C:\Users\Max\.platformio\packages\framework-arduinogd32\cores\arduino\main.cpp:51
   

   So really the lockup can happen at any time.

   • the timeout value is extremely large
   • there is no error handling if timeouts fail -- other libraries try to do I2C bus resets then
     • see https://www.i2c-bus.org/i2c-primer/analysing-obscure-problems/blocked-bus/
     • Wire library lockups recoverable with timeout but without hardware reset arduino/ArduinoCore-avr#326

   The Wire library needs an overhaul regarding error / timeout checking and I2C bus resetting.

   I can reproduce most lock-ups very determinstically when I flash the I2C OLED benchmark demo and reflash it in the middle of when it's writing to the screen.
3. maxgerhardt

   changed the title [-]Firmware hangup in `i2c_stop()`[/-] [+]Firmware hangup in `i2c_stop()` and other I2C functions[/+] on Oct 2, 2021
4. obra

   added a commit that references this issue on Nov 16, 2021

   Merge pull request #3 from keyboardio/jesse/usb-config-fallback

   ...

   c60c8dc