On Sun, 2009-05-10 at 08:03 -0700, Jim Stichnoth wrote:
> On Sun, May 10, 2009 at 1:44 AM, Hans Verkuil <[email protected]> wrote:
> >> > Here is what dmesg says about my card:
> >> > ivtv:  Start initialization, version 1.1.0
> >
> > This is quite old. Sliced VBI was broken for quite some time and it wasn't
> > fixed until ivtv version 1.3 if I'm not mistaken. I recommend upgrading to
> > a newer kernel first (from memory: 2.6.26 or up).
> 
> FWIW, I just tried the same experiments with a test install of
> MythDora 10.21 (kernel 2.6.27.9-159, ivtv 1.4.0), with the same
> results -- raw VBI has good captions, sliced VBI has nothing.

Jim,

Before I go mucking around with the cx25840 driver, could you run the
following steps to see if they make things better:

1. For your test install, get and build the latest ivtv and cx25840
drivers from 

http://linuxtv.org/hg/v4l-dvb/archive/tip.tar.bz2

Unpack, 'make menuconfig', 'make', 'make install' (as root), 'make
unload' (as root) and run 'modprobe ivtv'

The make menuconfig is optional, make sure you leave the
CONFIG_V4L_ADV_DBG (IIRC) enabled.

You also may want to build the v4l-dbg utility that's under v4l2-apps,
since the steps that follow assume the latest version.


2. Start up an S-Video capture with Sliced VBI.


3. Verify, as root (note you may have to use something other
than /dev/video1 - that's just where my PVR-150 card is):

# v4l2-dbg -d /dev/video1 -S
host0: cx23416    revision 0x00000000
i2c 0x1b: wm8775     revision 0x00000000
i2c 0x44: cx25843    revision 0x00008433

# v4l2-dbg -d /dev/video1 -c cx25840 -g 0x104
ioctl: VIDIOC_DBG_G_REGISTER
Register 0x00000104 = 0h (0d  00000000b)

# v4l2-dbg -d /dev/video1 -c cx25840 -g 0x105
ioctl: VIDIOC_DBG_G_REGISTER
Register 0x00000105 = dch (220d  11011100b)

# v4l2-dbg -d /dev/video1 -c cx25840 -g 0x106
ioctl: VIDIOC_DBG_G_REGISTER
Register 0x00000106 = 4h (4d  00000100b)


4. Then turn off the impedance boost for the Luma signal:

# v4l2-dbg -d /dev/video1 -c cx25840 -s 0x106 0x00

And wait for your app to play through it's current buffered up video to
see if the change gives you VBI back.



5. If not, then check the Automatic variable gain amplifier setting for
the luma signal:

# v4l2-dbg -d /dev/video1 -c cx25840 -g 0x488
ioctl: VIDIOC_DBG_G_REGISTER
Register 0x00000488 = 17h (23d  00010111b)

The top of scale is 0x3f, so if it's greater than 0x37 or so, then turn
on the extra 12 dB of gain for the Luma signal:

# v4l2-dbg -d /dev/video1 -c cx25840 -s 0x104 0x1

and again wait for the app to play through it's currently buffered up
video to see if you get sliced VBI back.


6. If that still doesn't work, try the different combinations of having
the extra 12 dB of gain on or off and the impedeance boost on or off.


That will tell me if it's CX25843 analog front end problem.  If it's not
that, then we'll have to look somewhere else.  BTW, the CX2584x
datasheet is available from dl.ivtvdriver.org if you care to see what
the registers mean.

Regards,
Andy


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