circuitpython: Copying multiple larger files can hang the copy if autoreload is on

First reported by @theacodes. Considerable discord discussion starting about 7pm ET 2021-1-12 in #circuitpython

Seems to happen fairly often (though not always) on SAMD21. Not sure if it happens on SAMD51. Not tried on other boards.

Example, copying to a Metro M0 Express running near the tip of main. First erase the filesystem. Then, do not enter the REPL, but copy multiple larger files, e.g. like this set:

32278 Aug 29  2018 hit.wav
89134 Aug 29  2018 idle.wav
61164 Aug 29  2018 off.wav
75820 Aug 29  2018 on.wav
43438 Aug 29  2018 swing.wav

For me, one out of two times this caused the copy to hang.

@theacodes reports that a workaround is to copy one file at a time or to enter the REPL, so that auto-reload is not happening, and then copy.

This problem was not evident to @theacodes on 5.3.1.

About this issue

Original URL
State: closed
Created 3 years ago
Reactions: 1
Comments: 22 (15 by maintainers)

Most upvoted comments

Confirming workaround: suspending autoreload through supervisor.disable_autoreload() or entering the REPL allows files to be copied without issue.

This was discovered while programming Big Honking Buttons. The factory setup script copies a set of files to the device - one set is the following WAV files:

drwxr-xr-x  9 stargirl  staff   288B Jul 24 13:37 ./
drwxr-xr-x  9 stargirl  staff   288B Jan 12 21:00 ../
-rw-r--r--  1 stargirl  staff    19K Jul 24 13:37 clap.wav
-rw-r--r--  1 stargirl  staff    63K Jul 24 13:37 dist.wav
-rw-r--r--  1 stargirl  staff    21K Jul 24 13:37 go.wav
-rw-r--r--  1 stargirl  staff    17K Jul 24 13:37 honk.wav
-rw-r--r--  1 stargirl  staff    37K Jul 24 13:37 kick.wav
-rw-r--r--  1 stargirl  staff    38K Jul 24 13:37 reverse.wav
-rw-r--r--  1 stargirl  staff    65K Jul 24 13:37 snare.wav

These in particular trigger the issue and would cause writes to the device to hang. It seems BHB’s library code accessing the filesystem at startup may contribute to triggering the issue more often as well.

As a workaround, we are forcing the device into the REPL before copying files:

def force_into_repl(usb_device_id: str):
    """Forces a circuitpython device into the REPL."""
    port = serial_connect(usb_device_id)

    # Interrupt with Ctrl + C
    port.write(b"\x03")
    # Enter repl with enter after slight delay
    time.sleep(0.2)
    port.write(b"\n")
    port.close()

With that workaround, we can program devices consistently without hanging:

========== DEPLOYING CODE ==========
Waiting for CIRCUITPY drive...
Forcing BHB into repl (workaround for CircuitPython issue #3986)
Cleaning temporary files from src directories...
Downloading files to cache...
Using cached winterbloom_voltageio.py.
Copying files...
Copied factory/.cache/winterbloom_voltageio.py to lib
Copied firmware/winterbloom_bhb to lib
Copied samples to .
Copied examples to .
Copied firmware/LICENSE to .
Copied firmware/README.HTM to .
Copied examples/default.py to code.py
Flushing... 🚽
Done copying files, resetting...
Done!

theacodes on Jan 13, 2021

@hathach Make sure and read the discussion on #4075 too.

tannewt on Jan 28, 2021

thanks @dhalbert , I will take a break from rp2040 and switch to troubleshoot this tomorrow. There are a few of RP2040 usb issues (usbnet, webusb etc…) though those will probably take time since I will need to go through datasheet reading. Will ping you if I could find out anything.

hathach on Jan 28, 2021