MythTV unresponsive/lags with remote

Currently chasing this nagging issue: MythTV responds almost instantly when using the keyboard, but it lags (at best) when pressing a button on the remote. And it’s more than a lag, it actually seams to queue several button presses and then respond to each command all at once. Incidentally, this was never a problem prior to installing the PCHDTV 5500 capture card.

Running ‘irw’ before starting mythfrontend reveals that the raw output from lirc discretely captures each and every button press without any visible lag. However, after starting X, the remote becomes unresponsice. No solution (yet). Just links with some clues:

mythfrontend does no react on every remote/lirc ‘click’

MythTV mailing list thread: Where does the remote lag come from?

Most likely not the problem — since irw shows lirc working fine, but interesting none-the-less: Winfast DTV1000 Remote DVB Tuner Card — (towards the bottom — adjust kernel interrupt rate ‘HZ’ to 1000Hz).

And here’s an interesting one — indeed, ir_common is getting loaded by cx88xx (pchdtv5500 card).

Update: Christoph (lirc developer) indicates:

Debugging will be required for the capture card driver. Someone is
disabling interrupts too long. You should remove the driver for the
capture card to isolate the one that causes the problem.

Final Solution Update: (prompted by Jack’s comment)

Believe it or not, it turns out the problem was infrared noise/interference generated by my plasma TV.  The reason it worked using irw was because the screen was black and not generating much IR.  Coincidentally, I added the tuner card at about the same time I  got the plasma TV — so, my capture card cause-effect assumption was all wrong!

The solution was to wrap the IR receiver with several layers of cellophane, which acts as a filter for the near-visible spectrum IR.  Google the following words for other references:

plasma IR remote interference filter

This article recommends 6-8 layers of “Glad Press-n-seal” for the filter.

I didn’t believe this could be the problem till I threw a blanket over the TV and worked the remote while peaking behind the blanket — it worked perfectly.

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