22 Mar, 2011

3 commits

  • As video hardware pipelines become increasingly complex and
    configurable, the current hardware description through v4l2 subdevices
    reaches its limits. In addition to enumerating and configuring
    subdevices, video camera drivers need a way to discover and modify at
    runtime how those subdevices are connected. This is done through new
    elements called entities, pads and links.

    An entity is a basic media hardware building block. It can correspond to
    a large variety of logical blocks such as physical hardware devices
    (CMOS sensor for instance), logical hardware devices (a building block
    in a System-on-Chip image processing pipeline), DMA channels or physical
    connectors.

    A pad is a connection endpoint through which an entity can interact with
    other entities. Data (not restricted to video) produced by an entity
    flows from the entity's output to one or more entity inputs. Pads should
    not be confused with physical pins at chip boundaries.

    A link is a point-to-point oriented connection between two pads, either
    on the same entity or on different entities. Data flows from a source
    pad to a sink pad.

    Links are stored in the source entity. To make backwards graph walk
    faster, a copy of all links is also stored in the sink entity. The copy
    is known as a backlink and is only used to help graph traversal.

    The entity API is made of three functions:

    - media_entity_init() initializes an entity. The caller must provide an
    array of pads as well as an estimated number of links. The links array
    is allocated dynamically and will be reallocated if it grows beyond the
    initial estimate.

    - media_entity_cleanup() frees resources allocated for an entity. It
    must be called during the cleanup phase after unregistering the entity
    and before freeing it.

    - media_entity_create_link() creates a link between two entities. An
    entry in the link array of each entity is allocated and stores pointers
    to source and sink pads.

    When a media device is unregistered, all its entities are unregistered
    automatically.

    The code is based on Hans Verkuil initial work.

    Signed-off-by: Laurent Pinchart
    Signed-off-by: Sakari Ailus
    Acked-by: Hans Verkuil
    Signed-off-by: Mauro Carvalho Chehab

    Laurent Pinchart
     
  • The media_device structure abstracts functions common to all kind of
    media devices (v4l2, dvb, alsa, ...). It manages media entities and
    offers a userspace API to discover and configure the media device
    internal topology.

    Signed-off-by: Laurent Pinchart
    Acked-by: Hans Verkuil
    Signed-off-by: Mauro Carvalho Chehab

    Laurent Pinchart
     
  • The media_devnode structure provides support for registering and
    unregistering character devices using a dynamic major number. Reference
    counting is handled internally, making device drivers easier to write
    without having to solve the open/disconnect race condition issue over
    and over again.

    The code is based on video/v4l2-dev.c.

    [mchehab@redhat.com: Remove linux/smp_lock.h include to not break compilation on bisect]
    Signed-off-by: Laurent Pinchart
    Acked-by: Hans Verkuil
    Signed-off-by: Mauro Carvalho Chehab

    Laurent Pinchart
     

29 Dec, 2010

1 commit


16 Dec, 2009

1 commit


05 Jun, 2008

1 commit

  • After commit 039d40019f3c5e26ea50ec5af4270189f63365e1
    (V4L/DVB (7898): Fix VIDEO_MEDIA Kconfig logic)
    VIDEO_MEDIA is no longer usable in Makefile's for deciding
    which directories we enter, resulting in compile errors like the
    following with CONFIG_VIDEO_DEV=y, CONFIG_DVB_CORE=m:

    ...
    MODPOST 187 modules
    ...
    make[2]: *** [__modpost] Error 1

    The easiest solution is to always enter video/

    Signed-off-by: Adrian Bunk
    Acked-by: Ingo Molnar
    Signed-off-by: Mauro Carvalho Chehab

    Adrian Bunk
     

09 May, 2008

1 commit

  • Fix allmodconfig build bug introduced in latest -git by commit
    7c91f0624a9 ("V4L/DVB(7767): Move tuners to common/tuners"):

    LD kernel/built-in.o
    LD drivers/built-in.o
    ld: drivers/media/built-in.o: No such file: No such file or directory

    which happens if all media drivers are modular:

    http://redhat.com/~mingo/misc/config-Wed_Apr_30_09_24_48_CEST_2008.bad

    In that case there's no obj-y rule connecting all the built-in.o files and
    the link tree breaks.

    The fix is to add a guaranteed obj-y rule for the core vmlinux to build.
    (which results in an empty object file if all media drivers are modular)

    Signed-off-by: Ingo Molnar
    Acked-by: Sam Ravnborg
    Signed-off-by: Stephen Rothwell
    Signed-off-by: Linus Torvalds

    Ingo Molnar
     

30 Apr, 2008

1 commit


07 Apr, 2008

1 commit


14 Dec, 2007

1 commit


09 May, 2007

1 commit

  • Change Kconfig objects from "menu, config" into "menuconfig" so
    that the user can disable the whole feature without having to
    enter the menu first.
    Also remove one indirection (CONFIG_DVB) that does not seem to
    be really used inside the kernel.

    Signed-off-by: Jan Engelhardt
    Signed-off-by: Mauro Carvalho Chehab

    Jan Engelhardt
     

10 Sep, 2005

1 commit


17 Apr, 2005

1 commit

  • Initial git repository build. I'm not bothering with the full history,
    even though we have it. We can create a separate "historical" git
    archive of that later if we want to, and in the meantime it's about
    3.2GB when imported into git - space that would just make the early
    git days unnecessarily complicated, when we don't have a lot of good
    infrastructure for it.

    Let it rip!

    Linus Torvalds