I have a system based on the TX1 that’s being prepared for FCC certification testing. I’ve noticed that I’ve got some noise coming off the clock signal on the SD card, and it turns out that when a card is inserted, the clock signal is always running regardless of any data transaction that is happening. We haven’t noticed this before, and when I reverted back to to Jetpack 3.0/L4T24.2.1, I’m not seeing this behavior, the clock only runs when the card is being accessed.
I’m using a custom carrier board, but I went back to the nVidia dev board and I measured the same behavior on the dev board… clock is running constantly on Jetpack 3.1/L4T28.1 while the card is inserted, but Jetpack 3.0/L4T24.2.1 doesn’t have this problem.
This will impact my ability to pass FCC certification, and it appears to be a kernel driver issue with the latest L4T28.1. Is there anyone at nVidia who has seen this issue before? Is there a way to fix it?