Although I submit these patches as the previous reply suggestion, I am stilling wondering the IOMMU with USB controller. I think the most of USB controller didn't need to create entities in IOMMU to support scatterlist. Once the hcd supports that(sg_tablesize > 0), it could support infinite scatter pages? Randy Li (2): USB: dma: remove unused function prototype docs: driver-api: usb: update dma info Documentation/driver-api/usb/dma.rst | 48 +++++++--------------------- include/linux/usb.h | 16 ---------- 2 files changed, 11 insertions(+), 53 deletions(-) -- 2.41.0