From af7c58b1f5014bea181ef74d724ac960923dd403 Mon Sep 17 00:00:00 2001 From: Andy Walls Date: Sat, 28 Feb 2009 20:13:50 -0300 Subject: [PATCH] V4L/DVB (10854): cx18: Correct comments about vertical and horizontal blanking timings This change only affects comments. Signed-off-by: Andy Walls Signed-off-by: Mauro Carvalho Chehab --- drivers/media/video/cx18/cx18-av-core.c | 26 +++++++++++++++---------- drivers/media/video/cx18/cx18-av-core.h | 19 +++++++++++------- drivers/media/video/cx18/cx18-streams.c | 5 ++--- 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 aeeb3cfa3390..21f4be8393b7 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 fd0df4151211..2687a2c91ddd 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 ce65cc6c86e8..0932b76b2373 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; /* -- 2.34.1