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authorAndy Walls <awalls@radix.net>2009-02-28 20:13:50 -0300
committerMauro Carvalho Chehab <mchehab@redhat.com>2009-03-30 12:43:09 -0300
commitaf7c58b1f5014bea181ef74d724ac960923dd403 (patch)
tree9458933e440c8b777cd4f5b2cce0cdf00f7dcaac /drivers/media/video/cx18
parent583803d135b14d414e77b6d2b546a811cac9944e (diff)
V4L/DVB (10854): cx18: Correct comments about vertical and horizontal blanking timings
This change only affects comments. Signed-off-by: Andy Walls <awalls@radix.net> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'drivers/media/video/cx18')
-rw-r--r--drivers/media/video/cx18/cx18-av-core.c26
-rw-r--r--drivers/media/video/cx18/cx18-av-core.h19
-rw-r--r--drivers/media/video/cx18/cx18-streams.c5
3 files changed, 30 insertions, 20 deletions
diff --git a/drivers/media/video/cx18/cx18-av-core.c b/drivers/media/video/cx18/cx18-av-core.c
index aeeb3cfa339..21f4be8393b 100644
--- a/drivers/media/video/cx18/cx18-av-core.c
+++ b/drivers/media/video/cx18/cx18-av-core.c
@@ -292,23 +292,29 @@ void cx18_av_std_setup(struct cx18 *cx)
*
* vsync: always 6 half-lines of vsync pulses
* vactive: half lines of active video
- * vblank656: half lines, after line 3, of blanked video
- * vblank: half lines, after line 9, of blanked video
+ * vblank656: half lines, after line 3/mid-266, of blanked video
+ * vblank: half lines, after line 9/272, of blanked video
*
+ * As far as I can tell:
* vblank656 starts counting from the falling edge of the first
- * vsync pulse (start of line 4)
+ * vsync pulse (start of line 4 or mid-266)
* vblank starts counting from the after the 6 vsync pulses and
- * 6 equalization pulses (start of line 10)
+ * 6 or 5 equalization pulses (start of line 10 or 272)
*
* For 525 line systems the driver will extract VBI information
- * from lines 10 through 21. To avoid the EAV RP code from
- * toggling at the start of hblank at line 22, where sliced VBI
- * data from line 21 is stuffed, also treat line 22 as blanked.
+ * from lines 10-21 and lines 273-284.
*/
- vblank656 = 38; /* lines 4 through 22 */
- vblank = 26; /* lines 10 through 22 */
- vactive = 481; /* lines 23 through 262.5 */
+ vblank656 = 38; /* lines 4 - 22 & 266 - 284 */
+ vblank = 26; /* lines 10 - 22 & 272 - 284 */
+ vactive = 481; /* lines 23 - 263 & 285 - 525 */
+ /*
+ * For a 13.5 Mpps clock and 15,734.26 Hz line rate, a line is
+ * is 858 pixels = 720 active + 138 blanking. The Hsync leading
+ * edge should happen 1.2 us * 13.5 Mpps ~= 16 pixels after the
+ * end of active video, leaving 122 pixels of hblank to ignore
+ * before active video starts.
+ */
hactive = 720;
hblank = 122;
luma_lpf = 1;
diff --git a/drivers/media/video/cx18/cx18-av-core.h b/drivers/media/video/cx18/cx18-av-core.h
index fd0df415121..2687a2c91dd 100644
--- a/drivers/media/video/cx18/cx18-av-core.h
+++ b/drivers/media/video/cx18/cx18-av-core.h
@@ -89,16 +89,21 @@ struct cx18_av_state {
/*
* The VBI slicer starts operating and counting lines, begining at
- * slicer line count of 1, at D lines after the deassertion of VRESET
- * This staring field line, S, is 6 or 10 for 625 or 525 line systems.
- * Sliced ancillary data captured on VBI slicer line M is sent at the
- * beginning of the next VBI slicer line, VBI slicer line count N = M+1.
- * Thus when the VBI slicer reports a VBI slicer line number with
- * ancillary data, the IDID0 byte indicates VBI slicer line N.
- * The actual field line that the captured data comes from is
+ * slicer line count of 1, at D lines after the deassertion of VRESET.
+ * This staring field line, S, is 6 (& 319) or 10 (& 273) for 625 or 525
+ * line systems respectively. Sliced ancillary data captured on VBI
+ * slicer line M is inserted after the VBI slicer is done with line M,
+ * when VBI slicer line count is N = M+1. Thus when the VBI slicer
+ * reports a VBI slicer line number with ancillary data, the IDID0 byte
+ * indicates VBI slicer line N. The actual field line that the captured
+ * data comes from is
+ *
* L = M+(S+D-1) = N-1+(S+D-1) = N + (S+D-2).
*
+ * L is the line in the field, not frame, from which the VBI data came.
+ * N is the line reported by the slicer in the ancillary data.
* D is the slicer_line_delay value programmed into register 0x47f.
+ * S is 6 for 625 line systems or 10 for 525 line systems
* (S+D-2) is the slicer_line_offset used to convert slicer reported
* line counts to actual field lines.
*/
diff --git a/drivers/media/video/cx18/cx18-streams.c b/drivers/media/video/cx18/cx18-streams.c
index ce65cc6c86e..0932b76b237 100644
--- a/drivers/media/video/cx18/cx18-streams.c
+++ b/drivers/media/video/cx18/cx18-streams.c
@@ -413,9 +413,8 @@ static void cx18_vbi_setup(struct cx18_stream *s)
* 0x90 (Task HorizontalBlank)
* 0xd0 (Task EvenField HorizontalBlank)
*
- * We have set the digitzer to consider the first active line
- * as part of VerticalBlank as well so we don't have to look for
- * these problem codes nor lose the last line of sliced data.
+ * We have set the digitzer such that we don't have to worry
+ * about these problem codes.
*/
data[4] = 0xB0F0B0F0;
/*