Jetson agx xavier (MAX9295/MAX9296): one (AR0233) camera works, two cameras don't (CSI port too busy?)

btw we were interested whether maybe one HDR and one non-HDR stream work on the same de-serialiser. turns out that the answer is still no. also, it turns out that transitioning between modes some times gets the ISP or the VI (?) into a weird state that is only resolved with a hard reset:

kworker/0:1-815   [000] ....   760.826868: rtos_queue_peek_from_isr_failed: tstamp:24092875485 queue:0x0bcbcf78