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author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-06-03 20:59:38 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-06-03 20:59:38 -0700 |
commit | a98f670e41a99f53acb1fb33cee9c6abbb2e6f23 (patch) | |
tree | f8ae10a4cb91758ad7f9422053753a8c5d0f04dc /Documentation/userspace-api/media/dvb/dmx-fread.rst | |
parent | ee01c4d72adffb7d424535adf630f2955748fa8b (diff) | |
parent | 938b29db3aa9c293c7c1366b16e55e308f1a1ddd (diff) | |
download | linux-a98f670e41a99f53acb1fb33cee9c6abbb2e6f23.tar.gz linux-a98f670e41a99f53acb1fb33cee9c6abbb2e6f23.tar.bz2 linux-a98f670e41a99f53acb1fb33cee9c6abbb2e6f23.zip |
Merge tag 'media/v5.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull media updates from Mauro Carvalho Chehab:
- Media documentation is now split into admin-guide, driver-api and
userspace-api books (a longstanding request from Jon);
- The media Kconfig was reorganized, in order to make easier to select
drivers and their dependencies;
- The testing drivers now has a separate directory;
- added a new driver for Rockchip Video Decoder IP;
- The atomisp staging driver was resurrected. It is meant to work with
4 generations of cameras on Atom-based laptops, tablets and cell
phones. So, it seems worth investing time to cleanup this driver and
making it in good shape.
- Added some V4L2 core ancillary routines to help with h264 codecs;
- Added an ov2740 image sensor driver;
- The si2157 gained support for Analog TV, which, in turn, added
support for some cx231xx and cx23885 boards to also support analog
standards;
- Added some V4L2 controls (V4L2_CID_CAMERA_ORIENTATION and
V4L2_CID_CAMERA_SENSOR_ROTATION) to help identifying where the camera
is located at the device;
- VIDIOC_ENUM_FMT was extended to support MC-centric devices;
- Lots of drivers improvements and cleanups.
* tag 'media/v5.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (503 commits)
media: Documentation: media: Refer to mbus format documentation from CSI-2 docs
media: s5k5baf: Replace zero-length array with flexible-array
media: i2c: imx219: Drop <linux/clk-provider.h> and <linux/clkdev.h>
media: i2c: Add ov2740 image sensor driver
media: ov8856: Implement sensor module revision identification
media: ov8856: Add devicetree support
media: dt-bindings: ov8856: Document YAML bindings
media: dvb-usb: Add Cinergy S2 PCIe Dual Port support
media: dvbdev: Fix tuner->demod media controller link
media: dt-bindings: phy: phy-rockchip-dphy-rx0: move rockchip dphy rx0 bindings out of staging
media: staging: dt-bindings: phy-rockchip-dphy-rx0: remove non-used reg property
media: atomisp: unify the version for isp2401 a0 and b0 versions
media: atomisp: update TODO with the current data
media: atomisp: adjust some code at sh_css that could be broken
media: atomisp: don't produce errs for ignored IRQs
media: atomisp: print IRQ when debugging
media: atomisp: isp_mmu: don't use kmem_cache
media: atomisp: add a notice about possible leak resources
media: atomisp: disable the dynamic and reserved pools
media: atomisp: turn on camera before setting it
...
Diffstat (limited to 'Documentation/userspace-api/media/dvb/dmx-fread.rst')
-rw-r--r-- | Documentation/userspace-api/media/dvb/dmx-fread.rst | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/Documentation/userspace-api/media/dvb/dmx-fread.rst b/Documentation/userspace-api/media/dvb/dmx-fread.rst new file mode 100644 index 000000000000..25501be818f8 --- /dev/null +++ b/Documentation/userspace-api/media/dvb/dmx-fread.rst @@ -0,0 +1,87 @@ +.. Permission is granted to copy, distribute and/or modify this +.. document under the terms of the GNU Free Documentation License, +.. Version 1.1 or any later version published by the Free Software +.. Foundation, with no Invariant Sections, no Front-Cover Texts +.. and no Back-Cover Texts. A copy of the license is included at +.. Documentation/userspace-api/media/fdl-appendix.rst. +.. +.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections + +.. _dmx_fread: + +======================= +Digital TV demux read() +======================= + +Name +---- + +Digital TV demux read() + + +Synopsis +-------- + +.. c:function:: size_t read(int fd, void *buf, size_t count) + :name: dvb-dmx-read + +Arguments +--------- + +``fd`` + File descriptor returned by a previous call to :c:func:`open() <dvb-ca-open>`. + + ``buf`` + Buffer to be filled + +``count`` + Max number of bytes to read + +Description +----------- + +This system call returns filtered data, which might be section or Packetized +Elementary Stream (PES) data. The filtered data is transferred from +the driver’s internal circular buffer to ``buf``. The maximum amount of data +to be transferred is implied by count. + +.. note:: + + if a section filter created with + :c:type:`DMX_CHECK_CRC <dmx_sct_filter_params>` flag set, + data that fails on CRC check will be silently ignored. + + +Return Value +------------ + +On success 0 is returned. + +On error -1 is returned, and the ``errno`` variable is set +appropriately. + +.. tabularcolumns:: |p{2.5cm}|p{15.0cm}| + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + :widths: 1 16 + + - - ``EWOULDBLOCK`` + - No data to return and ``O_NONBLOCK`` was specified. + + - - ``EOVERFLOW`` + - The filtered data was not read from the buffer in due time, + resulting in non-read data being lost. The buffer is flushed. + + - - ``ETIMEDOUT`` + - The section was not loaded within the stated timeout period. + See ioctl :ref:`DMX_SET_FILTER` for how to set a timeout. + + - - ``EFAULT`` + - The driver failed to write to the callers buffer due to an + invalid \*buf pointer. + + +The generic error codes are described at the +:ref:`Generic Error Codes <gen-errors>` chapter. |