My R5E50 backend with HDHomerun dual tuner has been rock solid. But sometimes it would be good to have a third tuner. So I added an Air2PC rev 0.2 card (from ebay) today.

To test the new card, I fired up two frontends and selected live TV, which consumed the two HDHomerun tuners. But when I fire up a third front end and try to watch TV, the backend hangs. Sometimes the hang is so severe that I can't even ping the box.

Note that I've tried different configurations. Originally I tried to use the same input configuration with the Air2PC card that I set up for the HDHomerun. Then I created a new input configuration and went through a channel scan with the Air2PC card.

Regardless of the configuration, the system still hangs. Sometimes I get a little video out of the Air2PC card first. And sometimes it crashes with just a black or green screen.

Note that my backend is running on a Soyo SY-K7V Dragon Plus MOBO, which has a VIA chip set. So perhaps this is a DMA problem.

But I'm not looking forward to swapping motherboards right now, so I'm hoping that this is resolvable with my current hardware.

Any suggestions would be welcome.

_________________
Best,

Allen Cronce

I've played some more and found that I can hang the backend with a single frontend by selecting the Air2PC card via the "Y" key. It seems to take longer to hang (I could actually watch a little and change channels a couple of times), but that might be annectodal.

I'm not seeing any hints in the various logs as to the nature of the problem.

_________________
Best,

Allen Cronce

I use the same Air2PC cards as you're inquiring about and have had no problems with them. However, they are a little finicky. They take about 3-5 minutes to "initalize" after the backend starts, so they will not work for a short time after a reboot or stoppage of the backend.

So after about 5 minutes of "up time" on your backend, what does output, where N is the tuner number of your Air2PC card? The first tuner is 0, second is 1 and so on.

Here's a sample from my box:


FE_HAS_LOCK means that your tuner is locking to a signal. That's a good thing!

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Mike
My Hardware Profile

Thanks for your response mihanson.

I tried the femon command after the backend had been running for several hours and got very similar results. I got an FE_HAS_LOCK every time.

Unfortunately I still see the hang after a few seconds of watching live TV using the Air2PC tuner.

Any other suggestions?

_________________
Best,

Allen Cronce

Perhaps a DMA problem. It may be that your drives cannot keep up with the stream. Have you ensured DMA is turned on? The FE_MON confirms you can get a signal and since you said at times you can watch TV for a few seconds, I'd rule out the Air2PC being bad.

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Mike
My Hardware Profile

But the drive keeps up just fine with both of the HDHomerun tuners. In any case, DMA is on according to "hdparm /dev/hda":

One interesting point is that when the hang happens, it looks like the drive is being pounded. I can see the access light blinking like crazy.

But all network I/O ceases, and my backend is headless, so I can't tell what it's doing. But maybe the issue here is that pulling data from the card is crapping out my onboard NIC?

_________________
Best,

Allen Cronce

Have you tried flashing the BIOS or swapping PCI slots with the air2pc card?

I've moved the card from the first slot to the last and I've yet to see a hang after 20 minutes of playing around. I've even tried my test of running three frontends against the backend. So far, so good.

Thanks for the suggestion Joe. Although this experience has given me the willies regarding my motherboard. I should probably plan on updating to something a little more modern, and a little less VIA, at some point in the future.

_________________
Best,

Allen Cronce

I have heard other people having trouble with the certain PCI slots on some motherboards. There may be some sharing of resources between the AGP slot and that one. When you say the first slot, was it right next to the AGP before the move?

Yes, it was. And I'm using the onboard ethernet, which I think also maps to a PCI device. So maybe resource sharing was the problem.

On a related note, I'm wondering if I have the right backend configuration after monkeying with my settings trying to work around the problem. What I have now is two input configurations, one for the HDHomerun tuners, and one for the Air2PC.

But both input configurations scanned to the same set of available channels. Although the signal strength on the Air2PC is about 10-20% lower than the HDHomerun tuners.

Should I have two input configurations, or should I consolidate to only one?

_________________
Best,

Allen Cronce