From 849369d6c66d3054688672f97d31fceb8e8230fb Mon Sep 17 00:00:00 2001 From: root Date: Fri, 25 Dec 2015 04:40:36 +0000 Subject: initial_commit --- Documentation/DocBook/v4l/media-ioc-enum-links.xml | 207 +++++++++++++++++++++ 1 file changed, 207 insertions(+) create mode 100644 Documentation/DocBook/v4l/media-ioc-enum-links.xml (limited to 'Documentation/DocBook/v4l/media-ioc-enum-links.xml') diff --git a/Documentation/DocBook/v4l/media-ioc-enum-links.xml b/Documentation/DocBook/v4l/media-ioc-enum-links.xml new file mode 100644 index 00000000..d2fc73ef --- /dev/null +++ b/Documentation/DocBook/v4l/media-ioc-enum-links.xml @@ -0,0 +1,207 @@ + + + ioctl MEDIA_IOC_ENUM_LINKS + &manvol; + + + + MEDIA_IOC_ENUM_LINKS + Enumerate all pads and links for a given entity + + + + + + int ioctl + int fd + int request + struct media_links_enum *argp + + + + + + Arguments + + + + fd + + File descriptor returned by + open(). + + + + request + + MEDIA_IOC_ENUM_LINKS + + + + argp + + + + + + + + + Description + + To enumerate pads and/or links for a given entity, applications set + the entity field of a &media-links-enum; structure and initialize the + &media-pad-desc; and &media-link-desc; structure arrays pointed by the + pads and links fields. + They then call the MEDIA_IOC_ENUM_LINKS ioctl with a pointer to this + structure. + If the pads field is not NULL, the driver + fills the pads array with information about the + entity's pads. The array must have enough room to store all the entity's + pads. The number of pads can be retrieved with the &MEDIA-IOC-ENUM-ENTITIES; + ioctl. + If the links field is not NULL, the driver + fills the links array with information about the + entity's outbound links. The array must have enough room to store all the + entity's outbound links. The number of outbound links can be retrieved with + the &MEDIA-IOC-ENUM-ENTITIES; ioctl. + Only forward links that originate at one of the entity's source pads + are returned during the enumeration process. + + + struct <structname>media_links_enum</structname> + + &cs-str; + + + __u32 + entity + Entity id, set by the application. + + + struct &media-pad-desc; + *pads + Pointer to a pads array allocated by the application. Ignored + if NULL. + + + struct &media-link-desc; + *links + Pointer to a links array allocated by the application. Ignored + if NULL. + + + + + + + struct <structname>media_pad_desc</structname> + + &cs-str; + + + __u32 + entity + ID of the entity this pad belongs to. + + + __u16 + index + 0-based pad index. + + + __u32 + flags + Pad flags, see for more details. + + + +
+ + + Media pad flags + + + + + + MEDIA_PAD_FL_SINK + Input pad, relative to the entity. Input pads sink data and + are targets of links. + + + MEDIA_PAD_FL_SOURCE + Output pad, relative to the entity. Output pads source data + and are origins of links. + + + +
+ + + struct <structname>media_links_desc</structname> + + &cs-str; + + + struct &media-pad-desc; + source + Pad at the origin of this link. + + + struct &media-pad-desc; + sink + Pad at the target of this link. + + + __u32 + flags + Link flags, see for more details. + + + + + + + Media link flags + + + + + + MEDIA_LNK_FL_ENABLED + The link is enabled and can be used to transfer media data. + When two or more links target a sink pad, only one of them can be + enabled at a time. + + + MEDIA_LNK_FL_IMMUTABLE + The link enabled state can't be modified at runtime. An + immutable link is always enabled. + + + MEDIA_LNK_FL_DYNAMIC + The link enabled state can be modified during streaming. This + flag is set by drivers and is read-only for applications. + + + + + One and only one of MEDIA_PAD_FL_SINK and + MEDIA_PAD_FL_SOURCE must be set for every pad. + + + + &return-value; + + + + EINVAL + + The &media-links-enum; id references + a non-existing entity. + + + + + -- cgit v1.2.3