Hi Folks
I've ended up talking to a few people recently about LEDs.
CE and EE have four user lights which are often hooked up in different ways on each board.
Are there any common recommendations about default LED hook ups for the kernel (e.g. USR1 -> heartbeat, USR2 -> disk I/O, etc)?
Similarly it might be useful to have a couple of events nominated where we recommend a firmware level bootloader[1] change LED status. Some examples:
- Set USR1 on when bootloader starts up (a NOR/eMMC/SD is not empty light). - Set USR3 on when entering fastboot mode (if supported) - Set USR3 off when leaving fastboot mode, including via "fastboot boot" (if supported) - Set USR1 off and USR2, 3 and 4 on if bootloader panics.
Especially for CE board (where users often don't have a UART adapter) even the above simple hints that the bootloader has been fetched from somewhere is useful.
I know this can't be a rule, only "good advice" (like asking CE boards to put console on LS-UART1 if possible). However, is there any appetite to converge for the boards we have influence over?
Daniel.
[1] Here I definitely mean EDK2 rather than grub. If we have multiple chained firmware level bootloaders (e.g. LK -> u-boot) things are less clear although, as it happens, if *both* implemented the above proposal the results would still be perfectly useable from a user perspective.