[LAU] Cracking sound via USB (ALSA urb.c:480: frame 5 active: -18)

[Aurélien Leblond]

Ouch...

Unfortunately I have a laptop, so or I get to work... or I change it
altogether (and I just bought it two months ago...especially to play
music!).

What gives me hope though is that:
- I have en XHCI USB3 port on the same laptop... Module snd-usb-audio
doesn't work on it yet, but I don't despair.
- Most important is that yesterday, I compiled the 2.6.39 kernel with
irqthreads, setup the rtirq script, removed every module I wasn't
using to free the irqs (xhci for the moment, wifi, other sound cards,
etc...) and I was down to only 2/3 crackles (and 3 messages in dmesg)
when playing a song with Ardour3 and Hydrogen playing along.

I still have to test and turn off KMS as I have read another user who
reported the same crackles (but no error in dmesg, because he has to
have alsa compiled with debug option to get them) and improved a lot
the thing with this option off...

Strange that the HP Envy 17, which is apparently designed with music
production in mind isn't set up properly hardware wise to support USB
sound cards!