CAPS LOCK led doesn't work with dumbkbd because dumbkbd option disables the i8042 module write capability, so the i8042 can't write the led status to the keyboard controller. Unfortunately this is a side effect of dumbkbd option, but there can be others too. I digged a bit into kernel source code and found that both i8042 and atkbd modules affect the keyboard controller behavior, but I'm still experimenting...
CAPS LOCK led doesn't work with dumbkbd because dumbkbd option disables the i8042 module write capability, so the i8042 can't write the led status to the keyboard controller. Unfortunately this is a side effect of dumbkbd option, but there can be others too. I digged a bit into kernel source code and found that both i8042 and atkbd modules affect the keyboard controller behavior, but I'm still experimenting...