On Wed, Aug 30, 2023 at 6:20 PM Tomasz Figa <tfiga@xxxxxxxxxxxx> wrote: > On Wed, Aug 30, 2023 at 5:50 PM Hui Fang <hui.fang@xxxxxxx> wrote: ...... > > I wonder if only NXP met the "swiotlb buffer full" issue. In theory, > > when format is YUYV, those resolutions no greater than 320x240 (153600 > > bytes, which less than the max mapping size 256K ) can't meet the issue. > > But resolutions no less than 640x480 (307200 bytes), may have chances > > to trigger the issue. > > I think a combination of a device that can support scatter-gather, but requires > swiotlb is kind of rare. Most drivers would require a single contiguous DMA > address (and thus use videobuf2-dma-contig) and physical discontinuity would > be handled by an IOMMU (transparently to vb2). > > I guess one thing to ask you about your specific setup is whether it's expected > that the swiotlb ends up being used at all? Yes, the swiotlb ends up being used. We met the issue when bring up DeviceAsWebCam (android-14 new feature, android device works as a usb camera). BRs, Fang Hui
