Hi Hans, On Thu, Jun 08, 2023 at 10:46:28AM +0200, Hans Verkuil wrote: > On 05/05/2023 23:52, Sakari Ailus wrote: > > Add generic serial metadata mbus formats. These formats describe data > > width and packing but not the content itself. The reason for specifying > > such formats is that the formats as such are fairly device specific but > > they are still handled by CSI-2 receiver drivers that should not be aware > > of device specific formats. What makes generic metadata formats possible > > is that these formats are parsed by software only, after capturing the > > data to system memory. > > > > Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> > > --- > > .../media/v4l/subdev-formats.rst | 257 ++++++++++++++++++ > > include/uapi/linux/media-bus-format.h | 9 + > > 2 files changed, 266 insertions(+) > > > > diff --git a/Documentation/userspace-api/media/v4l/subdev-formats.rst b/Documentation/userspace-api/media/v4l/subdev-formats.rst > > index a3a35eeed708..1492fff58426 100644 > > --- a/Documentation/userspace-api/media/v4l/subdev-formats.rst > > +++ b/Documentation/userspace-api/media/v4l/subdev-formats.rst > > @@ -8234,3 +8234,260 @@ The following table lists the existing metadata formats. > > both sides of the link and the bus format is a fixed > > metadata format that is not configurable from userspace. > > Width and height will be set to 0 for this format. > > + > > +Generic Serial Metadata Formats > > +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > + > > +Generic serial metadata formats are used on serial busses where the actual data > > +content is more or less device specific but the data is transmitted and received > > +by multiple devices that do not process the data in any way, simply writing > > +it to system memory for processing in software at the end of the pipeline. > > + > > +The more specific variant describing the actual data is used on the internal > > +source pad of the originating sub-device. > > I'm a bit confused here: on which pads are these generic mbus formats > set? And who sets this? As with other pads, the user can set the format. In most cases only a single option is available whenever the device ourputs metadata over a stream (and thus uses on of the generic line based metadata formats). > > I.e. the internal source pad has e.g. MEDIA_BUS_FMT_META_FOOBAR_HIST as > specific format. It's routed to a source pad + stream pair for transfer > over CSI. Does that source pad + stream pair use the generic mediabus > format? Correct. -- Sakari Ailus
