[PATCHv10 17/26] Documentation: media: description of DMABUF exporting in V4L2
On Wed October 10 2012 16:46:36 Tomasz Stanislawski wrote: > This patch adds description and usage examples for exporting > DMABUF file descriptor in V4L2. > > Signed-off-by: Tomasz Stanislawski > Signed-off-by: Kyungmin Park > CC: linux-doc at vger.kernel.org > --- > Documentation/DocBook/media/v4l/compat.xml|3 + > Documentation/DocBook/media/v4l/io.xml|3 + > Documentation/DocBook/media/v4l/v4l2.xml |1 + > Documentation/DocBook/media/v4l/vidioc-expbuf.xml | 212 > + > 4 files changed, 219 insertions(+) > create mode 100644 Documentation/DocBook/media/v4l/vidioc-expbuf.xml > Acked-by: Hans Verkuil
Re: [PATCHv10 17/26] Documentation: media: description of DMABUF exporting in V4L2
On Wed October 10 2012 16:46:36 Tomasz Stanislawski wrote: > This patch adds description and usage examples for exporting > DMABUF file descriptor in V4L2. > > Signed-off-by: Tomasz Stanislawski > Signed-off-by: Kyungmin Park > CC: linux-...@vger.kernel.org > --- > Documentation/DocBook/media/v4l/compat.xml|3 + > Documentation/DocBook/media/v4l/io.xml|3 + > Documentation/DocBook/media/v4l/v4l2.xml |1 + > Documentation/DocBook/media/v4l/vidioc-expbuf.xml | 212 > + > 4 files changed, 219 insertions(+) > create mode 100644 Documentation/DocBook/media/v4l/vidioc-expbuf.xml > Acked-by: Hans Verkuil ___ dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel
[PATCHv10 17/26] Documentation: media: description of DMABUF exporting in V4L2
This patch adds description and usage examples for exporting
DMABUF file descriptor in V4L2.
Signed-off-by: Tomasz Stanislawski
Signed-off-by: Kyungmin Park
CC: linux-doc at vger.kernel.org
---
Documentation/DocBook/media/v4l/compat.xml|3 +
Documentation/DocBook/media/v4l/io.xml|3 +
Documentation/DocBook/media/v4l/v4l2.xml |1 +
Documentation/DocBook/media/v4l/vidioc-expbuf.xml | 212 +
4 files changed, 219 insertions(+)
create mode 100644 Documentation/DocBook/media/v4l/vidioc-expbuf.xml
diff --git a/Documentation/DocBook/media/v4l/compat.xml
b/Documentation/DocBook/media/v4l/compat.xml
index 50eb630..3dd9e78 100644
--- a/Documentation/DocBook/media/v4l/compat.xml
+++ b/Documentation/DocBook/media/v4l/compat.xml
@@ -2590,6 +2590,9 @@ ioctls.
Importing DMABUF file descriptors as a new IO method described
in .
+
+ Exporting DMABUF files using &VIDIOC-EXPBUF; ioctl.
+
diff --git a/Documentation/DocBook/media/v4l/io.xml
b/Documentation/DocBook/media/v4l/io.xml
index 0abb5cb..81d0ed4 100644
--- a/Documentation/DocBook/media/v4l/io.xml
+++ b/Documentation/DocBook/media/v4l/io.xml
@@ -488,6 +488,9 @@ DMA buffer from userspace using a file descriptor
previously exported for a
different or the same device (known as the importer role), or both. This
section describes the DMABUF importer role API in V4L2.
+Refer to DMABUF exporting for
+details about exporting V4L2 buffers as DMABUF file descriptors.
+
Input and output devices support the streaming I/O method when the
V4L2_CAP_STREAMING flag in the
capabilities field of &v4l2-capability; returned by
diff --git a/Documentation/DocBook/media/v4l/v4l2.xml
b/Documentation/DocBook/media/v4l/v4l2.xml
index 10ccde9..4d110b1 100644
--- a/Documentation/DocBook/media/v4l/v4l2.xml
+++ b/Documentation/DocBook/media/v4l/v4l2.xml
@@ -543,6 +543,7 @@ and discussions on the V4L mailing list.
&sub-enuminput;
&sub-enumoutput;
&sub-enumstd;
+&sub-expbuf;
&sub-g-audio;
&sub-g-audioout;
&sub-g-crop;
diff --git a/Documentation/DocBook/media/v4l/vidioc-expbuf.xml
b/Documentation/DocBook/media/v4l/vidioc-expbuf.xml
new file mode 100644
index 000..72dfbd2
--- /dev/null
+++ b/Documentation/DocBook/media/v4l/vidioc-expbuf.xml
@@ -0,0 +1,212 @@
+
+
+
+ioctl VIDIOC_EXPBUF
+&manvol;
+
+
+
+VIDIOC_EXPBUF
+Export a buffer as a DMABUF file descriptor.
+
+
+
+
+
+ int ioctl
+ int fd
+ int request
+ struct v4l2_exportbuffer
*argp
+
+
+
+
+
+Arguments
+
+
+
+ fd
+
+ &fd;
+
+
+
+ request
+
+ VIDIOC_EXPBUF
+
+
+
+ argp
+
+
+
+
+
+
+
+
+Description
+
+
+ Experimental
+ This is an experimental
+ interface and may change in the future.
+
+
+This ioctl is an extension to the memory
+mapping I/O method, therefore it is available only for
+V4L2_MEMORY_MMAP buffers. It can be used to export a
+buffer as a DMABUF file at any time after buffers have been allocated with the
+&VIDIOC-REQBUFS; ioctl.
+
+ To export a buffer, applications fill &v4l2-exportbuffer;. The
+ type field is set to the same buffer type as was
+previously used with &v4l2-requestbuffers; type .
+Applications must also set the index field. Valid
+index numbers range from zero to the number of buffers allocated with
+&VIDIOC-REQBUFS; (&v4l2-requestbuffers; count )
+minus one. For the multi-planar API, applications set the plane
+ field to the index of the plane to be exported. Valid planes
+range from zero to the maximal number of valid planes for the currently active
+format. For the single-planar API, applications must set plane
+ to zero. Additional flags may be posted in the
+flags field. Refer to a manual for open() for details.
+Currently only O_CLOEXEC is supported. All other fields must be set to zero.
+In the case of multi-planar API, every plane is exported separately using
+multiple VIDIOC_EXPBUF calls.
+
+ After calling VIDIOC_EXPBUF the fd
+ field will be set by a driver. This is a DMABUF file
+descriptor. The application may pass it to other DMABUF-aware devices. Refer to
+DMABUF importing for details about importing
+DMABUF files into V4L2 nodes. It is recommended to close a DMABUF file when it
+is no longer used to allow the associated memory to be reclaimed.
+
+
+
+
+ Examples
+
+
+ Exporting a buffer.
+
+int buffer_export(int v4lfd, &v4l2-buf-type; bt, int index, int *dmafd)
+{
+ &v4l2-exportbuffer; expbuf;
+
+ memset(&expbuf, 0, sizeof(expbuf));
+ expbuf.type = bt;
+ expbuf.index = index;
+ if (ioctl(v4lfd, &VIDIOC-EXPBUF;, &expbuf) == -1) {
+ perror("VIDIOC_EXPBUF");
+ return -1;
+ }
+
[PATCHv10 17/26] Documentation: media: description of DMABUF exporting in V4L2
This patch adds description and usage examples for exporting
DMABUF file descriptor in V4L2.
Signed-off-by: Tomasz Stanislawski
Signed-off-by: Kyungmin Park
CC: linux-...@vger.kernel.org
---
Documentation/DocBook/media/v4l/compat.xml|3 +
Documentation/DocBook/media/v4l/io.xml|3 +
Documentation/DocBook/media/v4l/v4l2.xml |1 +
Documentation/DocBook/media/v4l/vidioc-expbuf.xml | 212 +
4 files changed, 219 insertions(+)
create mode 100644 Documentation/DocBook/media/v4l/vidioc-expbuf.xml
diff --git a/Documentation/DocBook/media/v4l/compat.xml
b/Documentation/DocBook/media/v4l/compat.xml
index 50eb630..3dd9e78 100644
--- a/Documentation/DocBook/media/v4l/compat.xml
+++ b/Documentation/DocBook/media/v4l/compat.xml
@@ -2590,6 +2590,9 @@ ioctls.
Importing DMABUF file descriptors as a new IO method described
in .
+
+ Exporting DMABUF files using &VIDIOC-EXPBUF; ioctl.
+
diff --git a/Documentation/DocBook/media/v4l/io.xml
b/Documentation/DocBook/media/v4l/io.xml
index 0abb5cb..81d0ed4 100644
--- a/Documentation/DocBook/media/v4l/io.xml
+++ b/Documentation/DocBook/media/v4l/io.xml
@@ -488,6 +488,9 @@ DMA buffer from userspace using a file descriptor
previously exported for a
different or the same device (known as the importer role), or both. This
section describes the DMABUF importer role API in V4L2.
+Refer to DMABUF exporting for
+details about exporting V4L2 buffers as DMABUF file descriptors.
+
Input and output devices support the streaming I/O method when the
V4L2_CAP_STREAMING flag in the
capabilities field of &v4l2-capability; returned by
diff --git a/Documentation/DocBook/media/v4l/v4l2.xml
b/Documentation/DocBook/media/v4l/v4l2.xml
index 10ccde9..4d110b1 100644
--- a/Documentation/DocBook/media/v4l/v4l2.xml
+++ b/Documentation/DocBook/media/v4l/v4l2.xml
@@ -543,6 +543,7 @@ and discussions on the V4L mailing list.
&sub-enuminput;
&sub-enumoutput;
&sub-enumstd;
+&sub-expbuf;
&sub-g-audio;
&sub-g-audioout;
&sub-g-crop;
diff --git a/Documentation/DocBook/media/v4l/vidioc-expbuf.xml
b/Documentation/DocBook/media/v4l/vidioc-expbuf.xml
new file mode 100644
index 000..72dfbd2
--- /dev/null
+++ b/Documentation/DocBook/media/v4l/vidioc-expbuf.xml
@@ -0,0 +1,212 @@
+
+
+
+ioctl VIDIOC_EXPBUF
+&manvol;
+
+
+
+VIDIOC_EXPBUF
+Export a buffer as a DMABUF file descriptor.
+
+
+
+
+
+ int ioctl
+ int fd
+ int request
+ struct v4l2_exportbuffer
*argp
+
+
+
+
+
+Arguments
+
+
+
+ fd
+
+ &fd;
+
+
+
+ request
+
+ VIDIOC_EXPBUF
+
+
+
+ argp
+
+
+
+
+
+
+
+
+Description
+
+
+ Experimental
+ This is an experimental
+ interface and may change in the future.
+
+
+This ioctl is an extension to the memory
+mapping I/O method, therefore it is available only for
+V4L2_MEMORY_MMAP buffers. It can be used to export a
+buffer as a DMABUF file at any time after buffers have been allocated with the
+&VIDIOC-REQBUFS; ioctl.
+
+ To export a buffer, applications fill &v4l2-exportbuffer;. The
+ type field is set to the same buffer type as was
+previously used with &v4l2-requestbuffers; type .
+Applications must also set the index field. Valid
+index numbers range from zero to the number of buffers allocated with
+&VIDIOC-REQBUFS; (&v4l2-requestbuffers; count )
+minus one. For the multi-planar API, applications set the plane
+ field to the index of the plane to be exported. Valid planes
+range from zero to the maximal number of valid planes for the currently active
+format. For the single-planar API, applications must set plane
+ to zero. Additional flags may be posted in the
+flags field. Refer to a manual for open() for details.
+Currently only O_CLOEXEC is supported. All other fields must be set to zero.
+In the case of multi-planar API, every plane is exported separately using
+multiple VIDIOC_EXPBUF calls.
+
+ After calling VIDIOC_EXPBUF the fd
+ field will be set by a driver. This is a DMABUF file
+descriptor. The application may pass it to other DMABUF-aware devices. Refer to
+DMABUF importing for details about importing
+DMABUF files into V4L2 nodes. It is recommended to close a DMABUF file when it
+is no longer used to allow the associated memory to be reclaimed.
+
+
+
+
+ Examples
+
+
+ Exporting a buffer.
+
+int buffer_export(int v4lfd, &v4l2-buf-type; bt, int index, int *dmafd)
+{
+ &v4l2-exportbuffer; expbuf;
+
+ memset(&expbuf, 0, sizeof(expbuf));
+ expbuf.type = bt;
+ expbuf.index = index;
+ if (ioctl(v4lfd, &VIDIOC-EXPBUF;, &expbuf) == -1) {
+ perror("VIDIOC_EXPBUF");
+ return -1;
+ }
+
+
