[2.6 patch] PAL-M support fix for CX88 chipsets

From: Mauro Carvalho Chehab
Date: Tue May 03 2005 - 07:49:53 EST


This patch fixes PAL-M chroma subcarrier frequency (FSC) to its correct value of 3.5756115 MHz and adjusts horizontal total samples for PAL-M, according with formula Line Draw Time / (4*FSC), where Line Draw Time is 63.555 us.
Without this patch, the Notch subcarrier filter was trying to capture using NTSC-M frequency, which is very close, but not equal. This could result in Black and White or miscolored frames.

-----

diff -puNr linux-2.6.12-rc3.org/drivers/media/video/cx88/cx88-core.c linux-2.6.12-rc3/drivers/media/video/cx88/cx88-core.c
--- linux-2.6.12-rc3.org/drivers/media/video/cx88/cx88-core.c 2005-04-20 21:03:14.000000000 -0300
+++ linux-2.6.12-rc3/drivers/media/video/cx88/cx88-core.c 2005-05-03 09:23:21.000000000 -0300
@@ -736,6 +736,9 @@ static unsigned int inline norm_fsc8(str
{
static const unsigned int ntsc = 28636360;
static const unsigned int pal = 35468950;
+ static const unsigned int palm = 28604892;
+
+ if (V4L2_STD_PAL_M & norm->id) return palm;

return (norm->id & V4L2_STD_625_50) ? pal : ntsc;
}
@@ -749,6 +752,8 @@ static unsigned int inline norm_notchfil

static unsigned int inline norm_htotal(struct cx88_tvnorm *norm)
{
+ // Should allways be Line Draw Time / 4FSC
+ if (V4L2_STD_PAL_M & norm->id) return 909;
return (norm->id & V4L2_STD_625_50) ? 1135 : 910;
}

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