Sdcard odb fix

[FoamyGuy]

Resolves #3309

Tested successfully with PyPortal.

@jepler helped create this fix for me. It was mentioned that there may need to be a similar solution added for framebuff APIs perhaps, that would be needed for the neopixels matrices if I understood correctly.

I think I have the appropriate hardware to try to tackle that now but I will need a bit more guidance into where that fix is it within the code and whether the same strategy used here is applicable for it.

[jepler]

What I'm thinking--but haven't tested:

STATIC void _refresh_display(framebufferio_framebufferdisplay_obj_t* self) {
    self->framebuffer_protocol->get_bufinfo(self->framebuffer, &self->bufinfo);
    if(!self->bufinfo.buf) {
        return;
    }
    displayio_display_core_start_refresh(&self->core);
    const displayio_area_t* current_area = _get_refresh_areas(self);

This code in shared-modules/framebufferio/FramebufferDisplay.c needs to be changed so that it checks the return value of displayio_display_core_start_refresh.

The use in shared-module/displayio/EPaperDisplay.c should be corrected too.

I simply used git grep to list up all the files where the string _refresh_display appeared.

[tannewt]

Is the top level background check not enough? https://github.com/adafruit/circuitpython/blob/main/shared-module/displayio/__init__.c#L43-L44

[jepler]

No, it's not.

We aren't entering background tasks recursively. We're entering refresh recursively: first from a foreground refresh() call, then from background tasks run during SD card accesses by OnDiskBitmap.

[tannewt]

Do we need the top level test then? Could we remove it?

[jepler]

I think the test at https://github.com/adafruit/circuitpython/blob/main/shared-module/displayio/__init__.c#L43-L44 can be removed with or without this, because of background_callback_run_all()s checks for !in_background_callback -- https://github.com/adafruit/circuitpython/blob/main/supervisor/shared/background_callback.c#L71-L75

[tannewt]

Ok, @FoamyGuy please remove that outer display check. If you don't have time, let us know and we can finish it. Thanks!

[FoamyGuy]

@tannewt I think the latest commit removes the check you were referring to. Let me know if I've misunderstood and removed something different, or if I missed something else that needs to go with it.

I did not build this or test on a device after the latest commit. I can try that out later tonight.

[tannewt]

Yup! Thank you. That is what I was thinking.

[FoamyGuy]

I had missed one instance of that boolean variable being used. The latest commit takes care of that.

I did also build this version tonight and run it on a PyPortal and verify that the adafruit_sdcard and ondiskbitmap are still working properly.

[tannewt]

Looks great! Thank you!