I'm trying to debug some code that implements a feature unit in an (incoming) USB device, based on an AT32UC3B1256 controller. The feature unit contains only a volume control, for which the host requests and I provide values for MAX, MIN, CUR, and RES. The host then tries to set RES to half the value I've set, even though the host has no business playing with MAX, MIN, or RES in the device. So I stall, as the USB audio spec says to do if the device is asked to modify an unmodifiable quantity. But if I don't stall, the host continuously counts down by half until it gets to the minimum, 1 (which is .0039 dB). With the stall, the host repeats the SET_RES request ten times at the same value, half of what I've defined RES to be. The upshot is that when the feature unit shows up (e.g. in xfce4 mixer) it's missing the slider; it just shows a mute button. Now I can't imagine that the host is at fault for not showing the slider; it must be something I'm missing in my code as no one else seems to have this problem. But just to satisfy my curiosity, what's the reason for the SET_RES countdown? ------------------------------------------------------------------------------ Dive into the World of Parallel Programming The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net/ _______________________________________________ Alsa-user mailing list Alsa-user@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-user
