Hi Sylwester, On Thursday 23 August 2012 21:24:12 Sakari Ailus wrote: > Sylwester Nawrocki wrote: > >> On Thu, Aug 23, 2012 at 11:51:26AM +0200, Sylwester Nawrocki wrote: > >>> The V4L2_CID_FRAMESIZE control determines maximum number > >>> of media bus samples transmitted within a single data frame. > >>> It is useful for determining size of data buffer at the > >>> receiver side. > >>> > >>> Signed-off-by: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx> > >>> Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx> > >>> --- > >>> > >>> Documentation/DocBook/media/v4l/controls.xml | 12 ++++++++++++ > >>> drivers/media/v4l2-core/v4l2-ctrls.c | 2 ++ > >>> include/linux/videodev2.h | 1 + > >>> 3 files changed, 15 insertions(+) > >>> > >>> diff --git a/Documentation/DocBook/media/v4l/controls.xml > >>> b/Documentation/DocBook/media/v4l/controls.xml index 93b9c68..ad5d4e5 > >>> 100644 > >>> --- a/Documentation/DocBook/media/v4l/controls.xml > >>> +++ b/Documentation/DocBook/media/v4l/controls.xml > >>> @@ -4184,6 +4184,18 @@ interface and may change in the future.</para> > >>> > >>> conversion. > >>> </entry> > >>> > >>> </row> > >>> > >>> + <row> > >>> + <entry > >>> spanname="id"><constant>V4L2_CID_FRAMESIZE</constant></entry> > >>> + <entry>integer</entry> > >>> + </row> > >>> + <row> > >>> + <entry spanname="descr">Maximum size of a data frame in media bus > >>> + sample units. This control determines maximum number of samples > >>> + transmitted per single compressed data frame. For generic raw > >>> + pixel formats the value of this control is undefined. This is > >>> + a read-only control. > >>> + </entry> > >>> + </row> > >>> > >>> <row><entry></entry></row> > >>> > >>> </tbody> > >>> > >>> </tgroup> > >>> > >>> diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c > >>> b/drivers/media/v4l2-core/v4l2-ctrls.c index b6a2ee7..0043fd2 100644 > >>> --- a/drivers/media/v4l2-core/v4l2-ctrls.c > >>> +++ b/drivers/media/v4l2-core/v4l2-ctrls.c > >>> @@ -727,6 +727,7 @@ const char *v4l2_ctrl_get_name(u32 id) > >>> > >>> case V4L2_CID_VBLANK: return "Vertical Blanking"; > >>> case V4L2_CID_HBLANK: return "Horizontal Blanking"; > >>> case V4L2_CID_ANALOGUE_GAIN: return "Analogue Gain"; > >>> > >>> + case V4L2_CID_FRAMESIZE: return "Maximum Frame Size"; > >> > >> I would put this to the image processing class, as the control isn't > >> related to image capture. Jpeg encoding (or image compression in > >> general) after all is related to image processing rather than capturing > >> it. > > > > All right, might make more sense that way. Let me move it to the image > > processing class then. It probably also makes sense to name it > > V4L2_CID_FRAME_SIZE, rather than V4L2_CID_FRAMESIZE. > > Hmm. While we're at it, as the size is maximum --- it can be lower --- > how about V4L2_CID_MAX_FRAME_SIZE or V4L2_CID_MAX_FRAME_SAMPLES, as the > unit is samples? > > Does sample in this context mean pixels for uncompressed formats and > bytes (octets) for compressed formats? It's important to define it as > we're also using the term "sample" to refer to data units transferred > over a parallel bus per a clock cycle. I agree with Sakari here, I find the documentation quite vague, I wouldn't understand what the control is meant for from the documentation only. > On serial busses the former meaning is more obvious. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
