Well, that was educational. It turns out that very few DMA drivers set the data fields required for bytes_transferred or memcpy_count to be updated, and the various RPi DMA drivers are not on that short list.
The easiest way to see that DMA is being used is to watch the interrupt counts like this:
The easiest way to see that DMA is being used is to watch the interrupt counts like this:
Code:
watch -n 0.5 'grep -E "(DMA|spi)" /proc/interrupts'Statistics: Posted by PhilE — Thu Jun 13, 2024 9:14 am