V4L/DVB (3178): bttv VBI fixes

- V4L2_(G|S|TRY)_FMT returned incorrect VBI start lines for PAL-M,
NTSC-JP, and PAL-60. They also returned an inaccurate VBI offset.
- V4L2_(G|S)_FMT and V4L2_TRY_FMT disagreed about the start of VBI
capturing in PAL and SECAM second field. Note the start line fixes
may break applications using VIDIOCSVBIFMT because this ioctl fails
when the driver does not support exactly the requested parameters.
- V4L2_TRY_FMT did not clear the reserved field in struct
v4l2_vbi_format.
- V4L2_(S|TRY)_FMT did not expect very large or small VBI start or
count values, returning wrong (but safe) counts due to an overflow.
- VIDIOCGVBIFMT confused V4L and V4L2 VBI flags. However this had no
effect because the flags have the same value and bttv never sets
them.
- In v4l_compat_translate_ioctl() the VIDIOC(G|S)VBIFMT code did not
expect V4L2 drivers supporting VBI formats besides V4L2_PIX_FMT_GREY.

Signed-off-by: Michael H. Schimek <mschimek@gmx.at>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@brturbo.com.br>

1 files changed, 22 insertions, 35 deletions

diff --git a/drivers/media/video/bttv-vbi.c b/drivers/media/video/bttv-vbi.c
index f4f58c60f15..72afdd64b88 100644
--- a/drivers/media/video/bttv-vbi.c
+++ b/drivers/media/video/bttv-vbi.c
@@ -31,6 +31,12 @@
 #include <asm/io.h>
 #include "bttvp.h"
 
+/* Offset from line sync pulse leading edge (0H) in 1 / sampling_rate:
+   bt8x8 /HRESET pulse starts at 0H and has length 64 / fCLKx1 (E|O_VTC
+   HSFMT = 0). VBI_HDELAY (always 0) is an offset from the trailing edge
+   of /HRESET in 1 / fCLKx1, and the sampling_rate tvnorm->Fsc is fCLKx2. */
+#define VBI_OFFSET ((64 + 0) * 2)
+
 #define VBI_DEFLINES 16
 #define VBI_MAXLINES 32
 
@@ -163,40 +169,30 @@ void bttv_vbi_setlines(struct bttv_fh *fh, struct bttv *btv, int lines)
 void bttv_vbi_try_fmt(struct bttv_fh *fh, struct v4l2_format *f)
 {
 	const struct bttv_tvnorm *tvnorm;
-	u32 start0,start1;
-	s32 count0,count1,count;
+	s64 count0,count1,count;
 
 	tvnorm = &bttv_tvnorms[fh->btv->tvnorm];
 	f->type = V4L2_BUF_TYPE_VBI_CAPTURE;
 	f->fmt.vbi.sampling_rate    = tvnorm->Fsc;
 	f->fmt.vbi.samples_per_line = 2048;
 	f->fmt.vbi.sample_format    = V4L2_PIX_FMT_GREY;
-	f->fmt.vbi.offset           = 244;
+	f->fmt.vbi.offset           = VBI_OFFSET;
 	f->fmt.vbi.flags            = 0;
-	switch (fh->btv->tvnorm) {
-	case 1: /* NTSC */
-		start0 = 10;
-		start1 = 273;
-		break;
-	case 0: /* PAL */
-	case 2: /* SECAM */
-	default:
-		start0 = 7;
-		start1 = 320;
-	}
 
-	count0 = (f->fmt.vbi.start[0] + f->fmt.vbi.count[0]) - start0;
-	count1 = (f->fmt.vbi.start[1] + f->fmt.vbi.count[1]) - start1;
-	count  = max(count0,count1);
-	if (count > VBI_MAXLINES)
-		count = VBI_MAXLINES;
-	if (count < 1)
-		count = 1;
+	/* s64 to prevent overflow. */
+	count0 = (s64) f->fmt.vbi.start[0] + f->fmt.vbi.count[0]
+		- tvnorm->vbistart[0];
+	count1 = (s64) f->fmt.vbi.start[1] + f->fmt.vbi.count[1]
+		- tvnorm->vbistart[1];
+	count  = clamp (max (count0, count1), 1LL, (s64) VBI_MAXLINES);
 
-	f->fmt.vbi.start[0] = start0;
-	f->fmt.vbi.start[1] = start1;
+	f->fmt.vbi.start[0] = tvnorm->vbistart[0];
+	f->fmt.vbi.start[1] = tvnorm->vbistart[1];
 	f->fmt.vbi.count[0] = count;
 	f->fmt.vbi.count[1] = count;
+
+	f->fmt.vbi.reserved[0] = 0;
+	f->fmt.vbi.reserved[1] = 0;
 }
 
 void bttv_vbi_get_fmt(struct bttv_fh *fh, struct v4l2_format *f)
@@ -209,21 +205,12 @@ void bttv_vbi_get_fmt(struct bttv_fh *fh, struct v4l2_format *f)
 	f->fmt.vbi.sampling_rate    = tvnorm->Fsc;
 	f->fmt.vbi.samples_per_line = 2048;
 	f->fmt.vbi.sample_format    = V4L2_PIX_FMT_GREY;
-	f->fmt.vbi.offset           = 244;
+	f->fmt.vbi.offset           = VBI_OFFSET;
+	f->fmt.vbi.start[0]         = tvnorm->vbistart[0];
+	f->fmt.vbi.start[1]         = tvnorm->vbistart[1];
 	f->fmt.vbi.count[0]         = fh->lines;
 	f->fmt.vbi.count[1]         = fh->lines;
 	f->fmt.vbi.flags            = 0;
-	switch (fh->btv->tvnorm) {
-	case 1: /* NTSC */
-		f->fmt.vbi.start[0] = 10;
-		f->fmt.vbi.start[1] = 273;
-		break;
-	case 0: /* PAL */
-	case 2: /* SECAM */
-	default:
-		f->fmt.vbi.start[0] = 7;
-		f->fmt.vbi.start[1] = 319;
-	}
 }
 
 /* ----------------------------------------------------------------------- */