From 995f5fefb0c6abba3688b3aadf40e422b64b814a Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Sat, 20 Feb 2010 09:41:03 -0300 Subject: V4L/DVB: media-spec: Fix documentation mistakes regarding I/O streaming The media spec contains several errors in the description of the I/O streaming ioctls, in particular with respect to the userptr I/O method. The most important change is that you really need to set count and index in v4l2_requestbuffer and v4l2_buffer when dealing with user pointer streaming. Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/v4l/vidioc-querybuf.xml | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'Documentation/DocBook/v4l/vidioc-querybuf.xml') diff --git a/Documentation/DocBook/v4l/vidioc-querybuf.xml b/Documentation/DocBook/v4l/vidioc-querybuf.xml index d834993e6191..e649805a4908 100644 --- a/Documentation/DocBook/v4l/vidioc-querybuf.xml +++ b/Documentation/DocBook/v4l/vidioc-querybuf.xml @@ -54,12 +54,13 @@ buffer at any time after buffers have been allocated with the &VIDIOC-REQBUFS; ioctl. Applications set the type field - of a &v4l2-buffer; to the same buffer type as previously + of a &v4l2-buffer; to the same buffer type as was previously used with &v4l2-format; type and &v4l2-requestbuffers; type, and the index field. Valid index numbers range from zero to the number of buffers allocated with &VIDIOC-REQBUFS; (&v4l2-requestbuffers; count) minus one. +The reserved field should to set to 0. After calling VIDIOC_QUERYBUF with a pointer to this structure drivers return an error code or fill the rest of the structure. @@ -68,8 +69,8 @@ the structure. V4L2_BUF_FLAG_MAPPED, V4L2_BUF_FLAG_QUEUED and V4L2_BUF_FLAG_DONE flags will be valid. The -memory field will be set to -V4L2_MEMORY_MMAP, the m.offset +memory field will be set to the current +I/O method, the m.offset contains the offset of the buffer from the start of the device memory, the length field its size. The driver may or may not set the remaining fields and flags, they are meaningless in -- cgit v1.2.3