/dev/cxadc0 stops sending data

[bc4040]

Having a weird issue where using cat /dev/cxadc0 > file.u8 will only generate a short burst of data.
However, hitting a keyboard key will nudge it and it will start capturing another short burst.
Holding down a key generally allows the data to flow as expected.

Same behavior exists when using ffplay to monitor the stream, or
cat /dev/cxadc0 | pv > file.u8
(shows a burst of data around 30-50MB/s, then drops to 0.)

kernel 5.10.0 / debian 11

[kmaftoum]

I'm seeing a similar issue, only getting a short burst of data then gives rubbish data, with lots of "cxadc 0000:04:00.0: interrupt stat 0x8000 masked 0x8000". So I'm suspecting something in the interrupt handling is a bit awry, or could possibly be a hardware fault with mine. This is a white generic CX25800 card, the VT-6X0 card in the docs. I'd like to test on the CX88 drivers to eliminate that but the card comes up as unsupported. Any clues?

[bc4040]

Just to follow up, removing all other pci-e cards and switching slots seemed to resolve my issue. It actually only worked in the furthest slot from the cpu on my Asus x79 board.

[kmaftoum]

Cheers - yeah tried that today to no avail, still just seems to stop completely after a short burst, or not get any data at all regardless of slot!

[kmaftoum]

Just to close the loop on this one for future readers - it was hardware, something to do with that motherboard, no combination of hardware swapping or kernel parameters made any effect. I swapped the whole machine out and installed the CX25800 card into another machine and all works fine...