Hi Hans, On Monday 30 July 2012 20:36:36 Hans Verkuil wrote: > On Sat July 28 2012 00:01:24 Sakari Ailus wrote: > > On Fri, Jul 27, 2012 at 04:25:04PM +0530, Prabhakar Lad wrote: > > > From: Manjunath Hadli <manjunath.hadli@xxxxxx> > > > > > > add new enum entries for supporting the media-bus formats on dm365. > > > These include some bayer and some non-bayer formats. > > > V4L2_MBUS_FMT_YDYUYDYV8_1X16 and V4L2_MBUS_FMT_UV8_1X8 are used > > > internal to the hardware by the resizer. > > > V4L2_MBUS_FMT_SBGGR10_ALAW8_1X8 represents the bayer ALAW format > > > that is supported by dm365 hardware. > > > > > > Acked-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> > > > Acked-by: Hans Verkuil <hans.verkuil@xxxxxxxxx> > > > Signed-off-by: Manjunath Hadli <manjunath.hadli@xxxxxx> > > > Signed-off-by: Lad, Prabhakar <prabhakar.lad@xxxxxx> > > > Cc: Sakari Ailus <sakari.ailus@xxxxxx> > > > Cc: Guennadi Liakhovetski <g.liakhovetski@xxxxxx> > > > --- > > > > > > Documentation/DocBook/media/v4l/subdev-formats.xml | 250 > > > +++++++++++++++++++- include/linux/v4l2-mediabus.h > > > | 10 +- > > > 2 files changed, 252 insertions(+), 8 deletions(-) > > > > > > diff --git a/Documentation/DocBook/media/v4l/subdev-formats.xml > > > b/Documentation/DocBook/media/v4l/subdev-formats.xml index > > > 49c532e..75dc275 100644 > > > --- a/Documentation/DocBook/media/v4l/subdev-formats.xml > > > +++ b/Documentation/DocBook/media/v4l/subdev-formats.xml > > > @@ -353,9 +353,9 @@ > > > > > > <listitem><para>The number of bits per pixel component. All components > > > are > > > transferred on the same number of bits. Common values are 8, 10 and > > > 12.</para> </listitem> > > > > > > - <listitem><para>If the pixel components are DPCM-compressed, a mention > > > of the - DPCM compression and the number of bits per compressed pixel > > > component.</para> - </listitem> > > > + <listitem><para>The compression (optional). If the pixel components > > > are > > > + ALAW- or DPCM-compressed, a mention of the compression scheme and the > > > + number of bits per compressed pixel component.</para></listitem> > > > > > > <listitem><para>The number of bus samples per pixel. Pixels that are > > > wider than the bus width must be transferred in multiple samples. > > > Common values are 1 and 2.</para></listitem> > > > > > > @@ -504,6 +504,74 @@ > > > > > > <entry>r<subscript>1</subscript></entry> > > > <entry>r<subscript>0</subscript></entry> > > > > > > </row> > > > > > > + <row id="V4L2-MBUS-FMT-SBGGR10-ALAW8-1X8"> > > > + <entry>V4L2_MBUS_FMT_SBGGR10_ALAW8_1X8</entry> > > > + <entry>0x3015</entry> > > > + <entry></entry> > > > + <entry>-</entry> > > > + <entry>-</entry> > > > + <entry>-</entry> > > > + <entry>-</entry> > > > + <entry>b<subscript>7</subscript></entry> > > > + <entry>b<subscript>6</subscript></entry> > > > + <entry>b<subscript>5</subscript></entry> > > > + <entry>b<subscript>4</subscript></entry> > > > + <entry>b<subscript>3</subscript></entry> > > > + <entry>b<subscript>2</subscript></entry> > > > + <entry>b<subscript>1</subscript></entry> > > > + <entry>b<subscript>0</subscript></entry> > > > + </row> > > > + <row id="V4L2-MBUS-FMT-SGBRG10-ALAW8-1X8"> > > > + <entry>V4L2_MBUS_FMT_SGBRG10_ALAW8_1X8</entry> > > > + <entry>0x3016</entry> > > > + <entry></entry> > > > + <entry>-</entry> > > > + <entry>-</entry> > > > + <entry>-</entry> > > > + <entry>-</entry> > > > + <entry>g<subscript>7</subscript></entry> > > > + <entry>g<subscript>6</subscript></entry> > > > + <entry>g<subscript>5</subscript></entry> > > > + <entry>g<subscript>4</subscript></entry> > > > + <entry>g<subscript>3</subscript></entry> > > > + <entry>g<subscript>2</subscript></entry> > > > + <entry>g<subscript>1</subscript></entry> > > > + <entry>g<subscript>0</subscript></entry> > > > + </row> > > > + <row id="V4L2-MBUS-FMT-SGRBG10-ALAW8-1X8"> > > > + <entry>V4L2_MBUS_FMT_SGRBG10_ALAW8_1X8</entry> > > > + <entry>0x3017</entry> > > > + <entry></entry> > > > + <entry>-</entry> > > > + <entry>-</entry> > > > + <entry>-</entry> > > > + <entry>-</entry> > > > + <entry>g<subscript>7</subscript></entry> > > > + <entry>g<subscript>6</subscript></entry> > > > + <entry>g<subscript>5</subscript></entry> > > > + <entry>g<subscript>4</subscript></entry> > > > + <entry>g<subscript>3</subscript></entry> > > > + <entry>g<subscript>2</subscript></entry> > > > + <entry>g<subscript>1</subscript></entry> > > > + <entry>g<subscript>0</subscript></entry> > > > + </row> > > > + <row id="V4L2-MBUS-FMT-SRGGB10-ALAW8-1X8"> > > > + <entry>V4L2_MBUS_FMT_SRGGB10_ALAW8_1X8</entry> > > > + <entry>0x3018</entry> > > > + <entry></entry> > > > + <entry>-</entry> > > > + <entry>-</entry> > > > + <entry>-</entry> > > > + <entry>-</entry> > > > + <entry>r<subscript>7</subscript></entry> > > > + <entry>r<subscript>6</subscript></entry> > > > + <entry>r<subscript>5</subscript></entry> > > > + <entry>r<subscript>4</subscript></entry> > > > + <entry>r<subscript>3</subscript></entry> > > > + <entry>r<subscript>2</subscript></entry> > > > + <entry>r<subscript>1</subscript></entry> > > > + <entry>r<subscript>0</subscript></entry> > > > + </row> > > > > > > <row id="V4L2-MBUS-FMT-SBGGR10-DPCM8-1X8"> > > > > > > <entry>V4L2_MBUS_FMT_SBGGR10_DPCM8_1X8</entry> > > > <entry>0x300b</entry> > > > > > > @@ -853,10 +921,16 @@ > > > > > > <title>Packed YUV Formats</title> > > > > > > <para>Those data formats transfer pixel data as (possibly > > > downsampled) Y, U > > > > > > - and V components. The format code is made of the following > > > information. + and V components. Some formats include dummy bits > > > in some of their samples + and are collectively referred to as > > > "YDYC" (Y-Dummy-Y-Chroma) formats. + One cannot rely on the values > > > of these dummy bits as those are undefined. + </para> > > > + <para>The format code is made of the following information. > > > > > > <itemizedlist> > > > > > > <listitem><para>The Y, U and V components order code, as transferred > > > on the > > > > > > - bus. Possible values are YUYV, UYVY, YVYU and VYUY.</para></listitem> > > > + bus. Possible values are YUYV, UYVY, YVYU and VYUY for formats with no > > > + dummy bit, and YDYUYDYV, YDYVYDYU, YUYDYVYD and YVYDYUYD for YDYC > > > formats. + </para></listitem> > > > > > > <listitem><para>The number of bits per pixel component. All components > > > are > > > transferred on the same number of bits. Common values are 8, 10 and > > > 12.</para> </listitem> > > > > I dicussed dummy vs. padding (zeros) with Laurent and we concluded we > > should use zero padding instead. The difference is that when processing > > the pixels no extra operations are necessary to get rid of the dummy data > > when the dummy bits are actually zero --- which in practice always is the > > case. > > > > I'm not aware of hardware that would assign padding bits (in this very > > purpose) that are a part of writes the width of bus width something else > > than zeros. It wouldn't make much sense either. > > > > So I suggest that dummy is replaced by padding which is defined to be > > zero. > > > > The letter in the format name could be 'Z', for example. > > > > Hans: what do you think? > > Bad idea. First of all, some hardware or FPGA can insert different values > there. It's something that Cisco uses in some cases: it makes it easier to > identify the dummy values if they have a non-zero fixed value. > > Another reason for not doing this is when such formats are used to display > video: you don't want to force the software to fill in the dummy values > with a specific value for no good reason. That would only cost extra CPU > cycles. On the other hand, when you process data that includes dummy bits stored in memory, knowing that the dummy bits are zero can save a mask operation. I don't have a strong opinion whether we should use zero or dummy bits for media bus formats. For memory formats I'd be inclined to use zero bits (at least when capturing). -- 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
