On 06/04/10 21:42, Andy Walls wrote: <snip> >> cx18-0 843: Video signal: present >> cx18-0 843: Detected format: NTSC-M >> cx18-0 843: Specified standard: NTSC-M >> cx18-0 843: Specified video input: Composite 7 >> cx18-0 843: Specified audioclock freq: 48000 Hz >> cx18-0 843: Detected audio mode: mono >> cx18-0 843: Detected audio standard: no detected audio standard > ^^^^^^^^^^^^^^^^^^^^^^^^^^ > | > And this is what makes me pull my hair out. ----+ > > Same card, same chipset, same firmware image, in the same PC and mobo, > same TV channel with the same RF signal, same analog tuner assembly, and > one '843 core detects the audio standard and the other '843 core > doesn't. :P > > If you have controlled the signal levels properly and used good cable > and grounding, the difference has to be in the analog tuner can. Either > it has gone bad, or it is picking up a lot of noise from somewhere. > > Come to think of it, a bad analog tuner assembly could explain the red > screen. > > Anyway, if *everthing* is the same, and one card works and one card > doesn't, there's nothing to be done in software - except implement > workaround that may not work. I *speculate* that you have a dying card. > To continue contributing to sales of Rogaine...
This evening I finally got a few minutes to rub together, so I've done an experiment. I shut down mythbackend, then started rmmoding as much of the cx18 stuff as I could positively identify using modules.dep. The idea was to "shut off" the cards with nothing else significant going on with the system, like a power-down or reboot. Then I modprobed cx18 and checked the status of both video devices. Both came up properly, both had sound. Tempting fate, I decided to try a reboot. Both cards came up properly, good sound, no red screens. Which makes me think back just a little bit... A few weeks back we had a bit of a heat wave here in Vermont - 80s even. The heat broke, and everything started cooling down after Friday, June 5th, in quite a marked way. (some 20 degrees cooler) Looking back I see that I reported that the card "came back" on June 6. It came up OK just now, and it's still cool. I'm wondering if there's a temperature effect here. Temperature is quite a significant factor in semiconductor performance. I'm going to keep an eye on this, and if sound goes away when it gets hot, I'll turn on the A/C for a few hours to cool the room and let the system thermally soak, then try again. To put this back into the "dying card" mindset, there are many failure and degradation modes in semiconductors, but one of those mechanisms is a threshold shift (Vt-shift) that tends to slow things down. Higher temperatures generally slow things down. I'm wondering about putting them both together. How is audio initialization done? I know I've seen you give parameters before to "slow things down", but don't know if that's relevant in this case. The weather is warming up toward next week, so it might be a good time to try some of these experiments. Dale Pontius _______________________________________________ ivtv-users mailing list [email protected] http://ivtvdriver.org/mailman/listinfo/ivtv-users
