On Tue, Sep 12, 2023 at 4:43 PM Hui Fang <hui.fang@xxxxxxx> wrote: > > On Tue, Sep 12, 2023 at 4:11 PM Tomasz Figa <tfiga@xxxxxxxxxxxx> wrote: > > Is your DMA device restricted only to the bottom-most 4 GB (32-bit DMA > > address)? If yes, would it make sense to also allocate from that area rather > > than bouncing the memory? > > The DMA device use 32-bit DMA address. > From user space, can't control the v4l2 buffer address, may still change the > code of vb2_dma_sg_alloc(). Right. You may want to try modifying vb2_dma_sg_alloc_compacted() to use dma_alloc_pages() instead of alloc_pages(). Best regards, Tomasz
