Charles Eidsness wrote:
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.
I'm still not completely sure what's going on but if I turn off acpi support in the kernel I no longer have this issue. I guess there's some sort of unexpected IRQ interaction. Strangely setting acpi=noirq doesn't solve the problem so maybe it's related to interrupts that ACPI is throwing up. It may just be related to the configuration of my laptop (Acer 8104).
Cheers, Charles