ws2812-pio-rp1: Could not open PIO

[Yanndroid]

Describe the bug

When my Raspberry PI 5 boots, it fails to load the ws2812-pio-rp1 driver.
Looking at the dmesg, it seems that it's related to a large HDD connected over USB and yes, without the HDD it works perfectly fine. The HDD in question is a WD 8TB MyBook and it takes a few seconds to spin up. During this time, the driver fails to load.
This might be just be an unfortunate coincidence rather than a bug.

I'm running a kernel built at this commit 954129f because I require a feature not released yet, but I can't remember if the release version also had this issue.

In my case, it would probably suffice if I somehow delay either the driver loading or HDD starting.

Steps to reproduce the behaviour

1. Append in /boot/firmware/config.txt

dtoverlay=ws2812-pio,gpio=17,num_leds=239,brightness=0

2. Connect a large HDD to USB (In my case, it's a WD 8TB MyBook)
3. Reboot

Device (s)

Raspberry Pi 5

System

$ cat /etc/rpi-issue
Raspberry Pi reference 2025-05-13
Generated using pi-gen, https://github.com/RPi-Distro/pi-gen, 5dabc7dc940059dfbc46af5d97b60a1e812523dd, stage2

$ vcgencmd version
2025/05/08 15:13:17
Copyright (c) 2012 Broadcom
version 69471177 (release) (embedded)

$ uname -a
Linux yannberry 6.12.58-v8-16k #1 SMP PREEMPT Sun Nov 16 01:56:04 UTC 2025 aarch64 GNU/Linux

Logs

[    2.210372] sd 0:0:0:0: [sda] Spinning up disk...
[    2.602951] input: pwr_button as /devices/platform/pwr_button/input/input0
[    3.230772] ..........
[   12.766994] platform rp1_firmware: deferred probe pending: (reason unknown)
[   12.766998] platform 1f00178000.pio: deferred probe pending: rp1-pio: failed to find RP1 firmware driver
[   13.470766] .......ready
[   19.615024] sd 0:0:0:0: [sda] Very big device. Trying to use READ CAPACITY(16).
[   19.629057] sd 0:0:0:0: [sda] 15628052480 512-byte logical blocks: (8.00 TB/7.28 TiB)
[   19.629059] sd 0:0:0:0: [sda] 4096-byte physical blocks
[   19.629453] sd 0:0:0:0: [sda] Write Protect is off
[   19.629455] sd 0:0:0:0: [sda] Mode Sense: 47 00 10 08
[   19.629950] sd 0:0:0:0: [sda] No Caching mode page found
[   19.629952] sd 0:0:0:0: [sda] Assuming drive cache: write through
[   19.690993]  sda: sda1
[   19.691085] sd 0:0:0:0: [sda] Attached SCSI disk
[   19.706750] ws2812-pio-rp1 ws2812_pio@11: error -ENOENT: Could not open PIO
[   19.706923] ws2812-pio-rp1 ws2812_pio@11: probe with driver ws2812-pio-rp1 failed with error -2
[   19.716115] mc: Linux media interface: v0.10
[   19.723117] rp1-firmware rp1_firmware: RP1 Firmware version eb39cfd516f8c90628aa9d91f52370aade5d0a55
[   19.723325] rp1-pio 1f00178000.pio: Created instance as pio0

Additional context

No response

[pelwell]

That sounds like a failure to defer the probe. It shouldn't be hard to fix.

[Yanndroid]

Thank you. Please let me know if I can help in any way.

[pelwell]

#7215 handles deferred probing and hard errors much better, and should fix the issue for you. In about 25 minutes you should be able to install a trial build using sudo rpi-update pulls/7215, after first reading these caveats: https://github.com/raspberrypi/rpi-update?tab=readme-ov-file#caveats

[Yanndroid]

I've installed your build, rebooted a few times and it initialized correctly everytime. Thank you 👍

[pelwell]

Thanks for reporting back. That PR has now been merged, so the fix will be in future kernel releases.