The boot diagnostics screen will report this as "UNKNOWN 3000mA". Unknown means that the USB-C voltage comparators didn't match any of the defined ranges.can you please explain what the CM5 will report on boot diagnostics screen when powered over GPIO as no USB-C PD handshake has happened (same as when CC0/CC1 were not connected)?"Take not that your Pi will assume 3A max current until you told him something else via EEPROM config."
On CM5 the firmware does not gate USB boot on having a 5A power supply because the power supply + CM5IO board is considered to be part of the overall system design so there's no need for the firmware to warn you.
It shouldn't be necessary to change the bootloader config settings and the bootloader will report the detected power supply via device-tree so that the OS / application can warn/ignore as desired.
As per your comment the PMIC will not apply any current limit, right?
On Pi5, Pi500 this is the same as USB-3A so the USB current limiter (external to the PMIC) is set to the low value and USB boot is not enabled unless the config.txt override is set.
On CM5 there is no on-module USB current limiter and USB boot is not restricted.
The "UNKNOWN" vs USB-C/USB-PD is not reported via DT so it will appear as something which the firmware believe can deliver at least 3A
Statistics: Posted by timg236 — Thu Mar 20, 2025 5:48 pm