Le jeudi 16 juin 2016 à 10:02 -0700, Steve Longerbeam a écrit : > I found the cause at least in my case. After enabling dynamic debug in > videobuf2-dma-contig.c, "v4l2-ctl -d/dev/video0 --stream-user=8" gives > me > > [ 468.826046] user data must be aligned to 64 bytes > > > > But even getting past that alignment issue, I've only tested userptr (in > mem2mem > driver) by giving the driver a user address of a mmap'ed kernel contiguous > buffer. A true discontiguous user buffer may not work, the IPU DMA does not > support scatter-gather.
If it's dma-contig, you'll need page aligned and contiguous memory. What some test application do when testing their driver with that, is to allocate memory using another device, or m2m device, that uses the same allocator. regards, Nicolas
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