QUERY · ISSUE

[RP2] machine.soft_reset() hangs when i2s is not deinitialized

openby mareclopened 2024-04-20updated 2024-08-07

bug

Checks

I agree to follow the MicroPython Code of Conduct to ensure a safe and respectful space for everyone.
I've searched for existing issues matching this bug, and didn't find any.

Port, board and/or hardware

RPI_PICO

MicroPython version

MicroPython v1.22.2 on 2024-02-22; Raspberry Pi Pico with RP2040

Reproduction

Initialize I2S device:

from machine import I2S
from machine import Pin

audio_out = I2S(0,
	sck=Pin(0), ws=Pin(1), sd=(2),
	mode=I2S.TX,
	bits=16,
	format=I2S.MONO,
	rate=44100,
	ibuf=20000)

Call machine.soft_reset()
Repeat 1, call audio_out.deinit() and no. 2 again

Expected behaviour

machine.soft_reset() resets machine
obraz

Observed behaviour

device hangs, requiring hardware reset or reconnecting USB
obraz

Additional Information

Verified on latest git commit and official release 1.22.2. This issue is pin-independent.

CANDIDATE · PULL REQUEST

ports/rp2: Disable correct IRQ for PIO1.

closedby Gadgetoidopened 2024-07-08updated 2024-07-23

port-rp2

Caught this while monkeying around trying to get some whacky custom C++ module to not hardlock on soft reset.

Assessment

S Sonnet · medium

Both items involve soft reset hangs on RP2040, and I2S on RP2 is implemented using PIO state machines internally — so there is a plausible code-path connection. However, the root causes are distinct. The query reports a hang when I2S is left initialized (deinit never called), meaning the PIO deinit path in rp2_pio.c is never reached. The PR fixes a wrong IRQ mask inside that deinit path (PIO0_IRQ_1 was being disabled instead of PIO1_IRQ_0). These are different failure modes: missing cleanup vs. incorrect IRQ handling during explicit cleanup. The PR would not resolve the reported I2S hang because the bug is in the initialization/teardown lifecycle of I2S on soft reset, not in which IRQ is cleared during PIO deinit.

Suggested action

No action needed — the PR does not resolve issue #14339. The I2S soft reset hang requires a fix in the I2S soft-reset/deinit path (extmod/machine_i2s.c or rp2-specific I2S code) to properly stop DMA and release PIO resources when soft_reset is triggered without an explicit deinit call. The PR may be worth referencing as context when investigating the root cause, since it confirms IRQ handling around PIO on RP2 is an active area of bugs.