I2C ValueError: GP15 in use if code.py stops for any reason

[tudorapo]

CircuitPython version and board name

Adafruit CircuitPython 10.0.0-beta.3 on 2025-08-29; Raspberry Pi Pico W with rp2040
Board ID:raspberry_pi_pico_w
UID:E6632C85930F4136
MAC:2C:CF:67:08:08:49

Code/REPL

import board
import busio
i2c1 = busio.I2C(board.GP15, board.GP14)

Behavior

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: GP15 in use

Description

If the code interrupted for any reason, be it a coding error, pressing ctrl-c, saving code.py, copying a new library, the code quits and the i2c pins remain locked.

This is happening on the second i2c bus of the pico pi w. On this bus there is an adafruit oled display, driven by the library adafruit_displayio_ssd1306. On the other i2c bus there are two sensors and running happily whatever I do.

Somehow the display does not cleans up after itself or unable to clean up at start.

Additional information

No response

[tannewt]

Is that all of your code.py? Displays and the busses they use aren't released during a reload. Instead, you must do displayio.release_displays() to release the display and its bus.

[tudorapo]

My apologies, I'm not sure how to post the code, but here it is.

And a fuller console output:

CO2: 2126 ppm ===========================> code running happily
Temp: 29.9/28.7 C
Humidity: 59/56 %
CO2: 2143 ppm
Temp: 29.7/28.7 C
Humidity: 60/56 %
CO2: 2224 ppm
Temp: 29.6/28.7 C
Humidity: 60/56 %

Code stopped by auto-reload. Reloading soon. =======>commenting out the i2c1 line and the display/draw part
soft reboot

Auto-reload is on. Simply save files over USB to run them or enter REPL to disable.
code.py output:
sreen start
sreen draws
Traceback (most recent call last):
  File "code.py", line 39, in <module>
NameError: name 'terminalio' isn't defined =======================> forgot to comment out this import

Code done running.

Press any key to enter the REPL. Use CTRL-D to reload.
soft reboot

Auto-reload is on. Simply save files over USB to run them or enter REPL to disable.
code.py output:
Traceback (most recent call last):
  File "code.py", line 13, in <module>
ValueError: GP15 in use =======================> argh. 

Code done running.

[tudorapo]

On the other hand, displayio.release_displays() seems to work, thank you. Never would have imagined that it works without configuring any displays.