From 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 Mon Sep 17 00:00:00 2001 From: Yunhong Jiang Date: Tue, 4 Aug 2015 12:17:53 -0700 Subject: Add the rt linux 4.1.3-rt3 as base Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang --- .../DocBook/media/v4l/vidioc-create-bufs.xml | 165 +++++++++++++++++++++ 1 file changed, 165 insertions(+) create mode 100644 kernel/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml (limited to 'kernel/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml') diff --git a/kernel/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml b/kernel/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml new file mode 100644 index 000000000..9b700a5f4 --- /dev/null +++ b/kernel/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml @@ -0,0 +1,165 @@ + + + ioctl VIDIOC_CREATE_BUFS + &manvol; + + + + VIDIOC_CREATE_BUFS + Create buffers for Memory Mapped or User Pointer or DMA Buffer + I/O + + + + + + int ioctl + int fd + int request + struct v4l2_create_buffers *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_CREATE_BUFS + + + + argp + + + + + + + + + Description + + + Experimental + This is an experimental + interface and may change in the future. + + + This ioctl is used to create buffers for memory +mapped or user pointer or DMA buffer I/O. It can be used as an alternative or in +addition to the VIDIOC_REQBUFS ioctl, when a tighter +control over buffers is required. This ioctl can be called multiple times to +create buffers of different sizes. + + To allocate the device buffers applications must initialize the +relevant fields of the v4l2_create_buffers structure. +The count field must be set to the number of +requested buffers, the memory field specifies the +requested I/O method and the reserved array must be +zeroed. + + The format field specifies the image format +that the buffers must be able to handle. The application has to fill in this +&v4l2-format;. Usually this will be done using the +VIDIOC_TRY_FMT or VIDIOC_G_FMT ioctl() +to ensure that the requested format is supported by the driver. Unsupported +formats will result in an error. + + The buffers created by this ioctl will have as minimum size the size +defined by the format.pix.sizeimage field. If the +format.pix.sizeimage field is less than the minimum +required for the given format, then sizeimage will be +increased by the driver to that minimum to allocate the buffers. If it is +larger, then the value will be used as-is. The same applies to the +sizeimage field of the +v4l2_plane_pix_format structure in the case of +multiplanar formats. + + When the ioctl is called with a pointer to this structure the driver +will attempt to allocate up to the requested number of buffers and store the +actual number allocated and the starting index in the +count and the index fields +respectively. On return count can be smaller than +the number requested. The driver may also increase buffer sizes if required, +however, it will not update sizeimage field values. +The user has to use VIDIOC_QUERYBUF to retrieve that +information. + + + struct <structname>v4l2_create_buffers</structname> + + &cs-str; + + + __u32 + index + The starting buffer index, returned by the driver. + + + __u32 + count + The number of buffers requested or granted. If count == 0, then + VIDIOC_CREATE_BUFS will set index + to the current number of created buffers, and it will check the validity of + memory and format.type. + If those are invalid -1 is returned and errno is set to &EINVAL;, + otherwise VIDIOC_CREATE_BUFS returns 0. It will + never set errno to &EBUSY; in this particular case. + + + __u32 + memory + Applications set this field to +V4L2_MEMORY_MMAP, +V4L2_MEMORY_DMABUF or +V4L2_MEMORY_USERPTR. See + + + &v4l2-format; + format + Filled in by the application, preserved by the driver. + + + __u32 + reserved[8] + A place holder for future extensions. + + + +
+ + + + &return-value; + + + + ENOMEM + + No memory to allocate buffers for memory +mapped I/O. + + + + EINVAL + + The buffer type (format.type field), +requested I/O method (memory) or format +(format field) is not valid. + + + + + -- cgit 1.2.3-korg