Re: [PATCH] cx25840 6.5MHz carrier detection fixes

["Aleksandr V. Piskunov" <aleksandr.v.piskunov@gmail.com>]

On Sat, Sep 26, 2009 at 04:12:59PM -0400, Andy Walls wrote:
> On Sat, 2009-09-26 at 00:16 +0300, Aleksandr V. Piskunov wrote:
> > cx25840:
> > Disable 6.5MHz carrier autodetection for PAL, always assume its DK.
> > Only try to autodetect 6.5MHz carrier for SECAM if user accepts both
> > system DK and L.
> > 
> > Signed-off-by: Aleksandr V. Piskunov <alexandr.v.piskunov@gmail.com>
> 
> Aleksandr,
> 
> I would like a little more time to look at your patch.

PAL part of the patch shouldn't affect any users IMHO, its the SECAM
part where we got SECAM-L users in France and SECAM-DK in Russia.

> 
> However, in the mean time, could you test the DK vs. L autodetection,
> without your patch, using the cx25840 firmware in
> 
> http://dl.ivtvdriver.org/ivtv/firmware/ivtv-firmware-20070217.tar.gz
> 
> ?
> 
> The MD5 sum of that firmware is:
> 
> $ md5sum /lib/firmware/v4l-cx25840.fw 
> 99836e41ccb28c7b373e87686f93712a  /lib/firmware/v4l-cx25840.fw
> 
> The cx25840 firmware in
> 
> http://dl.ivtvdriver.org/ivtv/firmware/ivtv-firmware-20080701.tar.gz
> http://dl.ivtvdriver.org/ivtv/firmware/ivtv-firmware.tar.gz
> 
> is probably wrong to use for the CX2584[0123] chips as it it actually
> CX23148 A/V core firmware - very similar but not the same.
> 

Tested following versions of v4l-cx25840.fw, no patch:

99836e41ccb28c7b373e87686f93712a
b3704908fd058485f3ef136941b2e513
647d818c6fc82f385ebfbbd4fb2def6d (comes as makoaudc.rom with win driver)

Same issue with all 3 versions of firmware tested, cold shutdown between
every test.
Quick description: PAL-DK source from cable, strong and clear signal.
On channel switch there are 3 typical outcomes
a) ~50% - DK audio system detected
b) ~40 - controller fails to detect standard, muted, may detect
   something later
c) ~10% - AM-L audio detected, playing some bogus static, may detect DK
   later

Of course there is a possibility that CX25843 doesn't like something
in IF that comes from xc2028 tuner, but as I said, signal ir very good
and picture/audio on every of 50+ channels is crisp and clear.