diff options
Diffstat (limited to 'Documentation/media')
| -rw-r--r-- | Documentation/media/kapi/mc-core.rst | 18 | ||||
| -rw-r--r-- | Documentation/media/uapi/gen-errors.rst | 10 | ||||
| -rw-r--r-- | Documentation/media/uapi/rc/rc-sysfs-nodes.rst | 13 | ||||
| -rw-r--r-- | Documentation/media/uapi/v4l/pixfmt-007.rst | 23 |
4 files changed, 42 insertions, 22 deletions
diff --git a/Documentation/media/kapi/mc-core.rst b/Documentation/media/kapi/mc-core.rst index 1a738e5f6056..0c05503eaf1f 100644 --- a/Documentation/media/kapi/mc-core.rst +++ b/Documentation/media/kapi/mc-core.rst @@ -162,13 +162,13 @@ framework provides a depth-first graph traversal API for that purpose. currently defined as 16. Drivers initiate a graph traversal by calling -:c:func:`media_entity_graph_walk_start()` +:c:func:`media_graph_walk_start()` The graph structure, provided by the caller, is initialized to start graph traversal at the given entity. Drivers can then retrieve the next entity by calling -:c:func:`media_entity_graph_walk_next()` +:c:func:`media_graph_walk_next()` When the graph traversal is complete the function will return ``NULL``. @@ -206,7 +206,7 @@ Pipelines and media streams When starting streaming, drivers must notify all entities in the pipeline to prevent link states from being modified during streaming by calling -:c:func:`media_entity_pipeline_start()`. +:c:func:`media_pipeline_start()`. The function will mark all entities connected to the given entity through enabled links, either directly or indirectly, as streaming. @@ -218,17 +218,17 @@ in higher-level pipeline structures and can then access the pipeline through the struct :c:type:`media_entity` pipe field. -Calls to :c:func:`media_entity_pipeline_start()` can be nested. +Calls to :c:func:`media_pipeline_start()` can be nested. The pipeline pointer must be identical for all nested calls to the function. -:c:func:`media_entity_pipeline_start()` may return an error. In that case, +:c:func:`media_pipeline_start()` may return an error. In that case, it will clean up any of the changes it did by itself. When stopping the stream, drivers must notify the entities with -:c:func:`media_entity_pipeline_stop()`. +:c:func:`media_pipeline_stop()`. -If multiple calls to :c:func:`media_entity_pipeline_start()` have been -made the same number of :c:func:`media_entity_pipeline_stop()` calls +If multiple calls to :c:func:`media_pipeline_start()` have been +made the same number of :c:func:`media_pipeline_stop()` calls are required to stop streaming. The :c:type:`media_entity`.\ ``pipe`` field is reset to ``NULL`` on the last nested stop call. @@ -245,7 +245,7 @@ operation must be done with the media_device graph_mutex held. Link validation ^^^^^^^^^^^^^^^ -Link validation is performed by :c:func:`media_entity_pipeline_start()` +Link validation is performed by :c:func:`media_pipeline_start()` for any entity which has sink pads in the pipeline. The :c:type:`media_entity`.\ ``link_validate()`` callback is used for that purpose. In ``link_validate()`` callback, entity driver should check diff --git a/Documentation/media/uapi/gen-errors.rst b/Documentation/media/uapi/gen-errors.rst index 6e983b9880fc..d39e34d1b19d 100644 --- a/Documentation/media/uapi/gen-errors.rst +++ b/Documentation/media/uapi/gen-errors.rst @@ -94,9 +94,17 @@ Generic Error Codes - Permission denied. Can be returned if the device needs write permission, or some special capabilities is needed (e. g. root) + - .. row 11 + + - ``EIO`` + + - I/O error. Typically used when there are problems communicating with + a hardware device. This could indicate broken or flaky hardware. + It's a 'Something is wrong, I give up!' type of error. + .. note:: - #. This list is not exaustive; ioctls may return other error codes. + #. This list is not exhaustive; ioctls may return other error codes. Since errors may have side effects such as a driver reset, applications should abort on unexpected errors, or otherwise assume that the device is in a bad state. diff --git a/Documentation/media/uapi/rc/rc-sysfs-nodes.rst b/Documentation/media/uapi/rc/rc-sysfs-nodes.rst index 6fb944fe21fd..3476ae29708f 100644 --- a/Documentation/media/uapi/rc/rc-sysfs-nodes.rst +++ b/Documentation/media/uapi/rc/rc-sysfs-nodes.rst @@ -92,15 +92,16 @@ This value may be reset to 0 if the current protocol is altered. Reading this file returns a list of available protocols to use for the wakeup filter, something like: -``rc5 rc6 nec jvc [sony]`` +``rc-5 nec nec-x rc-6-0 rc-6-6a-24 [rc-6-6a-32] rc-6-mce`` -The enabled wakeup protocol is shown in [] brackets. +Note that protocol variants are listed, so "nec", "sony", "rc-5", "rc-6" +have their different bit length encodings listed if available. -Writing "+proto" will add a protocol to the list of enabled wakeup -protocols. +Note that all protocol variants are listed. -Writing "-proto" will remove a protocol from the list of enabled wakeup -protocols. +The enabled wakeup protocol is shown in [] brackets. + +Only one protocol can be selected at a time. Writing "proto" will use "proto" for wakeup events. diff --git a/Documentation/media/uapi/v4l/pixfmt-007.rst b/Documentation/media/uapi/v4l/pixfmt-007.rst index 44bb5a7059b3..95a23a28c595 100644 --- a/Documentation/media/uapi/v4l/pixfmt-007.rst +++ b/Documentation/media/uapi/v4l/pixfmt-007.rst @@ -211,7 +211,13 @@ Colorspace sRGB (V4L2_COLORSPACE_SRGB) The :ref:`srgb` standard defines the colorspace used by most webcams and computer graphics. The default transfer function is ``V4L2_XFER_FUNC_SRGB``. The default Y'CbCr encoding is -``V4L2_YCBCR_ENC_601``. The default Y'CbCr quantization is full range. +``V4L2_YCBCR_ENC_601``. The default Y'CbCr quantization is limited range. + +Note that the :ref:`sycc` standard specifies full range quantization, +however all current capture hardware supported by the kernel convert +R'G'B' to limited range Y'CbCr. So choosing full range as the default +would break how applications interpret the quantization range. + The chromaticities of the primary colors and the white reference are: @@ -276,7 +282,7 @@ the following ``V4L2_YCBCR_ENC_601`` encoding as defined by :ref:`sycc`: Y' is clamped to the range [0…1] and Cb and Cr are clamped to the range [-0.5…0.5]. This transform is identical to one defined in SMPTE -170M/BT.601. The Y'CbCr quantization is full range. +170M/BT.601. The Y'CbCr quantization is limited range. .. _col-adobergb: @@ -288,10 +294,15 @@ The :ref:`adobergb` standard defines the colorspace used by computer graphics that use the AdobeRGB colorspace. This is also known as the :ref:`oprgb` standard. The default transfer function is ``V4L2_XFER_FUNC_ADOBERGB``. The default Y'CbCr encoding is -``V4L2_YCBCR_ENC_601``. The default Y'CbCr quantization is full -range. The chromaticities of the primary colors and the white reference -are: +``V4L2_YCBCR_ENC_601``. The default Y'CbCr quantization is limited +range. + +Note that the :ref:`oprgb` standard specifies full range quantization, +however all current capture hardware supported by the kernel convert +R'G'B' to limited range Y'CbCr. So choosing full range as the default +would break how applications interpret the quantization range. +The chromaticities of the primary colors and the white reference are: .. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| @@ -344,7 +355,7 @@ the following ``V4L2_YCBCR_ENC_601`` encoding: Y' is clamped to the range [0…1] and Cb and Cr are clamped to the range [-0.5…0.5]. This transform is identical to one defined in SMPTE -170M/BT.601. The Y'CbCr quantization is full range. +170M/BT.601. The Y'CbCr quantization is limited range. .. _col-bt2020: |