OS: 20.04
I am testing Raspberry PI PCIe USB expander hats.
USB 3 HUB is detected and flash drives automount to filesystem and files are read/write’able
Testing some mid-range USB Mics and Cameras, which have already been working with a USB PD hub on tachyon, mount up as /dev/video* or alsa devices respectively, but the pcie DMA → IOMMU crashed trying to write unmapped memory when beginning the isochronous a/v streams. Captured kernel debug logs from the command ffmpeg -f alsa -channels 1 -t 10 -i hw:0,0 test.wav. Same result capturing camera devices.
Log link:
Link to hat: