APPLIED: [SRU][Q:raspi/N:raspi][PATCH 0/1] Missing power LED on earlier models (LP: #2060942)
Juerg Haefliger
juerg.haefliger at canonical.com
Thu Jan 15 12:24:04 UTC 2026
Applied to Q/N linux-raspi master-next branch.
...Juerg
> BugLink: https://bugs.launchpad.net/bugs/2060942
>
> [ Impact ]
>
> The Pi Zero 2W, 2B, and 3B all fail to light their power LED once the kernel starts booting under noble (I hope this is only on noble; I only just noticed this during ISO testing and it's quite possible I missed it on earlier revisions...).
>
> Specifically, on the 2W (which only has a combined activity and power LED), /sys/class/leds/ACT/trigger is [actpwr] on RaspiOS, which makes it illuminate by default and blink off during mmc0 activity. This trigger setting appears to be unavailable under the Ubuntu kernel.
>
> On the 2B and 3B, the trigger is set to [none] which results in the LED initially illuminating while the bootloader is running and then disappearing. The default under RaspiOS is [input] which makes it illuminate normally, but switch off on undervolt. This trigger settging also appears unavailable under the Ubuntu kernel.
>
> [ Test Case ]
>
> 1. Observe LED behavior during boot.
> 2. Default modes should be [actpwr]/[input]:
> $ grep '' /sys/class/leds/*/trigger
>
> [ Where Problems Could Occur ]
>
> Additional kernel code is exercised at boot and later. Could cause the usual kernel issues: Crashes, hangs, freezes, splats, ...
>
> Juerg Haefliger (1):
> UBUNTU: [Configs] raspi: Set LEDS_TRIGGER_ACTPWR=y and
> LEDS_TRIGGER_INPUT=y
>
> debian.raspi/config/annotations | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
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