I have an unusual problem with my homebrew IR receiver. It works fine as long as the mythfrontend is not running (irw returns all the codes for the buttons pressed), but as soon as mythfrontend starts running, it stops working (no more data from irw and the frontend does not respond to the remote).

I had a closer look by running xmode2 with and without the frontend running and in both cases, repeatedly pressing the 1 button on my remote:

Here's what I saw without the frontend running:



and here's what I saw with the frontend running:



As you can see from the images, there is a recognisable pattern to the pulses when the frontend is not running, but something seems to be corrupting things when the frontend is running, resulting in no recognisable pattern (so it's not surprising it doesnt work).

Exiting the frontend makes it work like it did in the beginning again.

I was not doing anything in the frontend, it was just sitting at the main menu.

Anyone have any ideas as to what might be causing this corruption?

Hardware:
Diskless frontend on a Compaq EVO DS510.
2.4 GHz Pentuim 4.
256M RAM
FX5200 graphics via composite out to tv.

Is there a chance of an IRQ conflict with your serial port and some other device?

I considered that. AFAIK COM1 uses IRQ4 and cat /proc/interrupts doesnt show anything using that IRQ.

I discovered by a process of elimination that the module that was causing this interference was the gamecon module. I had configured my system to load that module at boot time so that I could use my playstation controllers connected to my parallel port to play mame games. I guess the frontend attempts to use the joystick device and this somehow interferes with lirc_serial.

Removing the module makes it work again.