[ESP32] I2C Interrupt problem since uprade to Espressif 1.1.0

[cyberman54]

I'm using u8x8 on ESP32 boards, programmed with Arduino Espressif32 core.
I2C display handling using driver U8X8_SSD1306_128X64_NONAME_HW_I2C

This worked perfectly until last days the Espressif32 core was updated from v1.0.2 to v1.1.0.

Since then i get this error during runtime:
[E][esp32-hal-i2c.c:594] i2c_isr_handler_default(): eject int=0x0, ena=0x0

And the display write speed is significantly reduced.

I'm not sure if this is a problem with u8x8 or the Espressif32 core. I'm not using any other I2C communication on the board.

Cross reference to u8x8:
olikraus/u8g2#646 (comment)

[cyberman54]

Wrong assignment, re-opened this issue at
platformio/platform-espressif32#107

[cyberman54]

Platformio owner pointed me back to here, so i reopen this issue here.

[stickbreaker]

@cyberman54 I just answered your issue on the platformio repo 107
updating to the newest core will solve most of that error message. The 'injection' error has only been caused by overlapping multi-task use of Wire() review your code to verify that all access to Wire() are single-threaded.

Chuck.

[cyberman54]

@stickbreaker Problem with the confusing debug messages is now solved, thanks to your pull request.
But it still have the problem with the interrupt injections with Espressif32 core 1.1.x, while the same code on the same device runs with Espressif32 core 1.0.2 without this problem.

[stickbreaker]

@cyberman54 the injection error is showing that the ISR was call, but the control structure was not configured for operation, there is a stage variable that has three possible values, STARTUP, RUNNING, and DONE. as you can see by the debug message, it's value was DONE. so the ISR should not have be triggered. Stage is set to done in three places of my code.

• first During ISR init(i2cProcQueue)
• second when the i2c transaction queue has completed (i2cExit)
• Third If the i2c transaction exceed the configured Timeout, (i2cProcQueue)
  Either a Bus Busy error
  Or a Gross Timeout error

Of these three sections of code, the first one was the source I traced down when Wire() was call by multiple tasks in a 'Ardunio' as Component under IDF, the MUTEX was disabled when Arduino is used as a component.

I cannot imagine how the second could result in an injection event. (it happens during interrupt context)

The Third could only happen if the timeout expired, the foreground task started cleaning up the timeout, but before it output the log messages of the failure (Gross timeout, Bus Busy) an i2c interrupt triggered. I cannot see this happening: here is the code. The interrupt would have to trigger before int_ena.val=0 but after stage=I2C_DONE. Well, It couldn't because it would have had to trigger after the int_ena.val=0 for 0x00 to be shown in the debug message. But int_ena controls the hardware interrupt generation. If it is cleared, no hardware interrupt can be generated by the i2c peripheral.
I'm confused. Something else is happening. My best guess is multi-tasking of Wire()

    } else { // GROSS timeout, shutdown ISR , report Timeout
        i2c->stage = I2C_DONE;
        i2c->dev->int_ena.val =0;
        i2c->dev->int_clr.val = 0x1FFF;
        if((i2c->queuePos==0)&&(i2c->byteCnt==0)) { // Bus Busy no bytes Moved
            reason = I2C_ERROR_BUSY;
            eBits = eBits | EVENT_ERROR_BUS_BUSY|EVENT_ERROR|EVENT_DONE;
#if ARDUHAL_LOG_LEVEL >= ARDUHAL_LOG_LEVEL_ERROR
            log_e(" Busy Timeout start=0x%x, end=0x%x, =%d, max=%d error=%d",tBefore,tAfter,(tAfter-tBefore),ticksTimeOut,i2c->error);
            i2cDumpI2c(i2c);
            i2cDumpInts(i2c->num);
#endif
        } else { // just a timeout, some data made it out or in.
            reason = I2C_ERROR_TIMEOUT;
            eBits = eBits | EVENT_ERROR_TIMEOUT|EVENT_ERROR|EVENT_DONE;

#if ARDUHAL_LOG_LEVEL >= ARDUHAL_LOG_LEVEL_ERROR
            log_e(" Gross Timeout Dead start=0x%x, end=0x%x, =%d, max=%d error=%d",tBefore,tAfter,(tAfter-tBefore),ticksTimeOut,i2c->error);
            i2cDumpI2c(i2c);
            i2cDumpInts(i2c->num);
#endif
        }
    }

Code that generated the Debug message "injection":

// sync between dispatch(i2cProcQueue) and worker(i2c_isr_handler_default)
typedef enum {
    //I2C_NONE=0,
    I2C_STARTUP=1,
    I2C_RUNNING,
    I2C_DONE
} I2C_STAGE_t;

    if(p_i2c->stage==I2C_DONE) { //get Out
        log_e("eject int=%p, ena=%p",activeInt,p_i2c->dev->int_ena.val);
        p_i2c->dev->int_ena.val = 0;
        p_i2c->dev->int_clr.val = activeInt; //0x1FFF;
        return;
}

As you can see this if() will only trigger if state==I2C_DONE. The only time I have seen this happen was when Wire() was called by multiple task simultaneously. The two hex value printed in the message show the interrupt that generated this call NONE, and the interrupts that are enabled to trigger this ISR NONE. This only happens when code to clear / disable interrupts is called during an active interrupt cycle.

I don't have a clue how the ISR was called out of sequence.

Chuck.

[cyberman54]

Hmm, sounds difficult. As my application code runs under espressif32 v1.0.2 without this i2c problem, i assume that this behaviour is caused by something that came in by upgrade Espressif32 to v1.1.x.

In my application code i don't use Wire() directly. But i am using u8g2 library to control an OLED I2C display. The author of u8g2 pointed out, that his library is using Wire.h in Arduino style.

My application uses RTos tasks, but u8g2 calls are centralized in one main task. But the main task will be interrupted by other tasks (which don't call Wire()).

[stickbreaker]

@cyberman54 are you using ANY other i2c code? mixing IDF i2c and Arduino i2c?

Chuck.

[cyberman54]

No. Only I2C component is the OLED display, controlled by u8g2 library.

[bartoszbielawski]

I have exactly the same problem. One I2C display that is controlled from a separate FreeRTOS task.
The class for the display does something and from the same thread I change Wire pin assignments and speed. Otherwise no other accesses.

[stickbreaker]

@cyberman54 @bartoszbielawski are you both using Platformio? I use Arduino. Can either or both of you make a small /simple example that shows this problem?

If I need to set up a Platformio environment I will, but I will probably need some help 😁

Chuck.

[cyberman54]

Chuck, you may just look to my repo:

https://github.com/cyberman54/ESP32-Paxcounter/tree/development?files=1

[bartoszbielawski]

@stickbreaker
Yes, I use PIO as well.
I have already written a minimal test program and I think it should be easy to run it in Arduino IDE:
https://gist.github.com/bartoszbielawski/bf9a03d6eb505b299c7fd6a8b641021c

The screen itself has some extra random dots and the printed number sometime jump few pixels back and forth + the error messages - check the end of the gist.