Hi, Cc: Robin On 12/14/20 2:57 PM, Alexandre Courbot wrote: > This driver uses the SG vb2 ops, but effectively only ever accesses the > first entry of the SG table, indicating that it expects a flat layout. > Switch it to use the contiguous ops to make sure this expected invariant Under what circumstances the sg table will has nents > 1? I came down to [1] but not sure I got it right. I'm afraid that for systems with low amount of system memory and when the memory become fragmented, the driver will not work. That's why I started with sg allocator. [1] https://elixir.bootlin.com/linux/v5.10.1/source/drivers/iommu/dma-iommu.c#L782 > is always enforced. Since the device is supposed to be behind an IOMMU > this should have little to none practical consequences beyond making the > driver not rely on a particular behavior of the SG implementation. > > Reported-by: Tomasz Figa <tfiga@xxxxxxxxxxxx> > Signed-off-by: Alexandre Courbot <acourbot@xxxxxxxxxxxx> > --- > Hi everyone, > > It probably doesn't hurt to fix this issue before some actual issue happens. > I have tested this patch on Chrome OS and playback was just as fine as with > the SG ops. > > drivers/media/platform/Kconfig | 2 +- > drivers/media/platform/qcom/venus/helpers.c | 9 ++------- > drivers/media/platform/qcom/venus/vdec.c | 6 +++--- > drivers/media/platform/qcom/venus/venc.c | 6 +++--- > 4 files changed, 9 insertions(+), 14 deletions(-) > > diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kconfig > index 35a18d388f3f..d9d7954111f2 100644 > --- a/drivers/media/platform/Kconfig > +++ b/drivers/media/platform/Kconfig > @@ -533,7 +533,7 @@ config VIDEO_QCOM_VENUS > depends on INTERCONNECT || !INTERCONNECT > select QCOM_MDT_LOADER if ARCH_QCOM > select QCOM_SCM if ARCH_QCOM > - select VIDEOBUF2_DMA_SG > + select VIDEOBUF2_DMA_CONTIG > select V4L2_MEM2MEM_DEV > help > This is a V4L2 driver for Qualcomm Venus video accelerator > diff --git a/drivers/media/platform/qcom/venus/helpers.c b/drivers/media/platform/qcom/venus/helpers.c > index 50439eb1ffea..859d260f002b 100644 > --- a/drivers/media/platform/qcom/venus/helpers.c > +++ b/drivers/media/platform/qcom/venus/helpers.c > @@ -7,7 +7,7 @@ > #include <linux/mutex.h> > #include <linux/slab.h> > #include <linux/kernel.h> > -#include <media/videobuf2-dma-sg.h> > +#include <media/videobuf2-dma-contig.h> > #include <media/v4l2-mem2mem.h> > #include <asm/div64.h> > > @@ -1284,14 +1284,9 @@ int venus_helper_vb2_buf_init(struct vb2_buffer *vb) > struct venus_inst *inst = vb2_get_drv_priv(vb->vb2_queue); > struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb); > struct venus_buffer *buf = to_venus_buffer(vbuf); > - struct sg_table *sgt; > - > - sgt = vb2_dma_sg_plane_desc(vb, 0); > - if (!sgt) > - return -EFAULT; > > buf->size = vb2_plane_size(vb, 0); > - buf->dma_addr = sg_dma_address(sgt->sgl); Can we do it: if (WARN_ON(sgt->nents > 1)) return -EFAULT; I understand that logically using dma-sg when the flat layout is expected by the hardware is wrong, but I haven't seen issues until now. > + buf->dma_addr = vb2_dma_contig_plane_dma_addr(vb, 0); > > if (vb->type == V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE) > list_add_tail(&buf->reg_list, &inst->registeredbufs); > diff --git a/drivers/media/platform/qcom/venus/vdec.c b/drivers/media/platform/qcom/venus/vdec.c > index 8488411204c3..3fb277c81aca 100644 > --- a/drivers/media/platform/qcom/venus/vdec.c > +++ b/drivers/media/platform/qcom/venus/vdec.c > @@ -13,7 +13,7 @@ > #include <media/v4l2-event.h> > #include <media/v4l2-ctrls.h> > #include <media/v4l2-mem2mem.h> > -#include <media/videobuf2-dma-sg.h> > +#include <media/videobuf2-dma-contig.h> > > #include "hfi_venus_io.h" > #include "hfi_parser.h" > @@ -1461,7 +1461,7 @@ static int m2m_queue_init(void *priv, struct vb2_queue *src_vq, > src_vq->io_modes = VB2_MMAP | VB2_DMABUF; > src_vq->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY; > src_vq->ops = &vdec_vb2_ops; > - src_vq->mem_ops = &vb2_dma_sg_memops; > + src_vq->mem_ops = &vb2_dma_contig_memops; > src_vq->drv_priv = inst; > src_vq->buf_struct_size = sizeof(struct venus_buffer); > src_vq->allow_zero_bytesused = 1; > @@ -1475,7 +1475,7 @@ static int m2m_queue_init(void *priv, struct vb2_queue *src_vq, > dst_vq->io_modes = VB2_MMAP | VB2_DMABUF; > dst_vq->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY; > dst_vq->ops = &vdec_vb2_ops; > - dst_vq->mem_ops = &vb2_dma_sg_memops; > + dst_vq->mem_ops = &vb2_dma_contig_memops; > dst_vq->drv_priv = inst; > dst_vq->buf_struct_size = sizeof(struct venus_buffer); > dst_vq->allow_zero_bytesused = 1; > diff --git a/drivers/media/platform/qcom/venus/venc.c b/drivers/media/platform/qcom/venus/venc.c > index 1c61602c5de1..a09550cd1dba 100644 > --- a/drivers/media/platform/qcom/venus/venc.c > +++ b/drivers/media/platform/qcom/venus/venc.c > @@ -10,7 +10,7 @@ > #include <linux/pm_runtime.h> > #include <linux/slab.h> > #include <media/v4l2-mem2mem.h> > -#include <media/videobuf2-dma-sg.h> > +#include <media/videobuf2-dma-contig.h> > #include <media/v4l2-ioctl.h> > #include <media/v4l2-event.h> > #include <media/v4l2-ctrls.h> > @@ -1001,7 +1001,7 @@ static int m2m_queue_init(void *priv, struct vb2_queue *src_vq, > src_vq->io_modes = VB2_MMAP | VB2_USERPTR | VB2_DMABUF; > src_vq->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY; > src_vq->ops = &venc_vb2_ops; > - src_vq->mem_ops = &vb2_dma_sg_memops; > + src_vq->mem_ops = &vb2_dma_contig_memops; > src_vq->drv_priv = inst; > src_vq->buf_struct_size = sizeof(struct venus_buffer); > src_vq->allow_zero_bytesused = 1; > @@ -1017,7 +1017,7 @@ static int m2m_queue_init(void *priv, struct vb2_queue *src_vq, > dst_vq->io_modes = VB2_MMAP | VB2_USERPTR | VB2_DMABUF; > dst_vq->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY; > dst_vq->ops = &venc_vb2_ops; > - dst_vq->mem_ops = &vb2_dma_sg_memops; > + dst_vq->mem_ops = &vb2_dma_contig_memops; > dst_vq->drv_priv = inst; > dst_vq->buf_struct_size = sizeof(struct venus_buffer); > dst_vq->allow_zero_bytesused = 1; > -- regards, Stan
