On Sat, 2010-04-10 at 18:28 -0400, Mark Lord wrote:
> On 15/03/10 07:51 AM, Andy Walls wrote:
> > On Sun, 2010-03-14 at 22:48 -0400, Mark Lord wrote:
> >> On 03/02/10 07:40, Andy Walls wrote:
> ..
> >> after updating to the tip of the v4l2-dvb git tree last week,
> >> I've been hitting the "no audio" on analog recordings bug much more often.
> >>
> >> Digging through google, it appears this problem has been around as long
> >> as the cx18 driver has existed, with no clear resolution. Lots of people
> >> have reported it to you before, and nobody has found a silver bullet fix.
> ..
> > Here are all the potential problem areas I can think of:
> >
> > 1. A/V digitizer/decoder audio detection firmware load and init. (I've
> > added firmware readback verification to try and head this off.)
> >
> > 2. A/V digitizer decoder audio microcontroller hard reset and "soft"
> > reset sequencing. (I think the cx18 driver has this wrong ATM.)
> >
> > 3. APU load and init. (The double load is to fix a DTV TS stream bug on
> > every other APU& CPU firmware load sequence. The APU_AI_RESET is to
> > fix the audio bitrate problem on first capture after a double firmware
> > load.)
> >
> > 4. AI1 Mux setting failing when switching between the internal A/V
> > decoder's I2S output and the external I2S inputs. (I thought I had this
> > fixed, but I don't have detailed register specs for that register - so
> > maybe not.)
> >
> > 5. A/V decoder audio clock PLL stops operating due to being programmed
> > out of range. (This was a problem for 32 ksps audio a while ago, but
> > I'm pretty confident I have it fixed.)
> >
> > 6. A/V decoder analog frontend setup for SIF wrong?. (I fixed this due
> > to a problen Helen Buus reported with cable TV.)
> >
> > I think #2 is the real problem. I just started to disassmble the
> > digitizer firmware 2 nights ago to see if I could get some insight as to
> > how to properly reset it.
> >
> > I've got a first WAG at fixing the resets of the audio microcontroller's
> > resets at:
> >
> > http://linuxtv.org/hg/~awalls/cx18-audio
> >
> > If it doesn't work, change the CXADEC_AUDIO_SOFT_RESET register define
> > from 0x810 to 0x9cc, although that may not work either.
> ..
> > Thanks for the troubleshooting and reporting.
> ..
>
> Back at this again today, after a month away from it -- getting tired
> of watching "Survivor" with closed-captioning instead of audio. :)
>
> I pulled your (Andy) repository today, and merged the cx18 audio reset
> changes from it into today's tip from v4l-dvb. Patch attached for reference.
>
> So far, so good. I'll keep tabs on it over time, and see if the audio
> is stable, or if it still fails once in a while.
Hmmm. Darren's having problems (loss of video/black screen) with my
patches under my cx18-audio repo, but I'm not quite convinced he doesn't
have some other PCI bus problem either.
Anyway, my plan now is this:
1. on cx18-av-core.c:input_change()
a. set register 0x808 for audio autodetection
b. restart the format detection loop
c. set or reset a 1.5 second timeout
2. after the timer expires, if no audio standard was detected,
a. force the audio standard by programming register 0x808
(e.g. BTSC for NTSC-M)
b. restart the format detection loop so the micrcontroller will
do the unmute when it detects audio
Darren is in NTSC-M/BTSC land. What TV standard are you dealing with?
Regards,
Andy
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