Hi All,
I'm developing a USB DAC and I've ran into an issue that has me scratching my head. Every once in a while (30 seconds or so) my USB DAC gets sent a USB frame that's missing a few samples, unless I'm also streaming audio through my laptop's built-in audio interface, i.e. playing audio through my USB DAC alone and I get dropped data, playing audio through my USB DAC and the built-in audio device at the same time (unique streams to each device) and I get no dropped data to my USB DAC. Once I stop playing audio on the built-in device I start getting dropped data to my USB DAC again.
The USB DAC is using the standard USB Audio drivers, and the built-in device is an RealTek ALC880 HDA device connected through an Intel 82801. I'm guessing that the hda driver is configuring some global parameter when it's in active playback mode that the USB driver should maybe also be setting. Any ideas? I've already played around with lspci (the USB interface on my laptop is PCI based) but can't see any differences in PCI configuration between when I'm playing audio on the biult-in device and when I'm not.
Thanks! Charles