Hi Tomasz, 2013/12/31 Tomasz Stanislawski <t.stanislaws@xxxxxxxxxxx>: > Hi Chuanbo Weng, > > I suspect that the problem might be caused by difference > between size of DMABUF object and buffer size in V4L2. Thanks for your reply! I agree with you because my experiment prove it (Even when the bo is bigget than frame size, not smaller!!!). > What is the content of v4l2_format returned by VIDIOC_G_FMT? The content is V4L2_PIX_FMT_YUYV. (And if the content V4L2_PIX_FMT_MJPEG, this issue doesn't happen.) > What is the content of V4l2_buffer structure passed by VIDIOC_QBUF? The fd in v4l2_buffer structure is fd of gem object created by DRM_IOCTL_MODE_CREATE_DUMB. I've upload the program that can reproduce this issue on intel platform. You just need to clone it from https://github.com/strgnm/v4l2-dmabuf-test.git Then build and run as said in README. > > Regards, > Tomasz Stanislawski > > On 12/31/2013 03:42 AM, Chuanbo Weng wrote: >> Hi Laurent, >> >> >> 2013/12/29 Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>: >>> Hi Chuanbo, >>> >>> On Friday 27 December 2013 09:55:40 Chuanbo Weng wrote: >>>>> Hi all, >>>>> >>>>> (My environment is intel platform, HD4000 GPU, kernel 3.10.19, logitech >>>>> 270 webcam) >>>>> >>>>> As title said, I discover this issue when I run the program shown by >>>>> Laurent Pinchart: >>>>> http://www.mail-archive.com/linux-media@xxxxxxxxxxxxxxx/msg54806.html >>>>> >>>>> If the frame is (width, height) = (640, 480), DMABUF works well. >>>>> If the frame is (width, height) = (160, 120), v4lfd receives no event. >>>>> >>>>> And I dig into drm kernel code, find that: i915_gem_create will create a >>>>> GPU buffer object on intel platform. The size of GPU bo will be bigger >>>>> than frame size, for the reason that i915_gem_create will roundup the bo >>>>> size to multiple of PAGE_SIZE when the frame is (width, height) = (160, >>>>> 120). For (width, height) = (640, 480), the frame size is already multiple >>>>> of PAGE_SIZE, so GPU bo is exactly equal to frame size. >>> >>> That should in theory not be an issue). This might be a stupid question, but >>> have you tried to capture 160x120 images directly (with yavta for instance) >>> without using DMABUF ? >> >> Thanks for your reply! Please forgive me if it's a stupid question >> because I'm new in camera >> and v4l2 region. Yes, of course, I have tried to capture 160x120 >> images using yavta and v4l-utils >> without using DMABUF (using MMAP), it works well. So it proves the >> camera support this width >> and height.I strongly recommend you to tried 160x120 images using >> DMABUF on your machine, >> because I have tried 3 cameras (two logiteh, one microsoft) and all of >> them don't work. >>> >>>>> I also dump the uvc driver infomation, there is some infomation i >>>>> think maybe important: >>>>> uvcvideo: Stream 1 error event 07 01 len 4 >>>>> >>>>> Looking forward to the discussion! >>> >>> -- >>> Regards, >>> >>> Laurent Pinchart >>> >> >> Thanks, >> Chuanbo Weng >> > -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
