Merge master.kernel.org:/pub/scm/linux/kernel/git/mchehab/v4l-dvb

[sfrench/cifs-2.6.git] / drivers / media / video / bt8xx / bttv-vbi.c

diff --git a/drivers/media/video/bt8xx/bttv-vbi.c b/drivers/media/video/bt8xx/bttv-vbi.c
index e20ff238e4092b4f1811b6741ae3005bf145bd94..63676e7bd635f6b403a69be86e0e24d602c56337 100644 (file)
--- a/drivers/media/video/bt8xx/bttv-vbi.c
+++ b/drivers/media/video/bt8xx/bttv-vbi.c
@@ -31,11 +31,16 @@
 #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)
+/* Offset from line sync pulse leading edge (0H) to start of VBI capture,
+   in fCLKx2 pixels.  According to the datasheet, VBI capture starts
+   VBI_HDELAY fCLKx1 pixels from the tailing edgeof /HRESET, and /HRESET
+   is 64 fCLKx1 pixels wide.  VBI_HDELAY is set to 0, so this should be
+   (64 + 0) * 2 = 128 fCLKx2 pixels.  But it's not!  The datasheet is
+   Just Plain Wrong.  The real value appears to be different for
+   different revisions of the bt8x8 chips, and to be affected by the
+   horizontal scaling factor.  Experimentally, the value is measured
+   to be about 244.  */
+#define VBI_OFFSET 244
 
 #define VBI_DEFLINES 16
 #define VBI_MAXLINES 32
@@ -184,7 +189,7 @@ void bttv_vbi_try_fmt(struct bttv_fh *fh, struct v4l2_format *f)
                - 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);
+       count  = clamp (max (count0, count1), (s64) 1, (s64) VBI_MAXLINES);
 
        f->fmt.vbi.start[0] = tvnorm->vbistart[0];
        f->fmt.vbi.start[1] = tvnorm->vbistart[1];