Hmm, but a single jack doesn't mean that the driver should only provide a single "device" for the card? The interface/signal is still different, no? On 13 January 2016 at 22:19, Tanu Kaskinen <tanuk at iki.fi> wrote: > Hi, > > Related to previous discussions[1][2][3] about dealing with volume on > certain type of usb sound cards, I'd like to make it possible to enable > and disable hardware volume for individual cards and/or ports in > pavucontrol. > > Here's the specific use case: the Terratec Aureon Dual USB sound card > has a single output jack that can used in both analog and digital modes > (there are other similar usb sound cards too). PulseAudio has no way to > know which mode is in use. Hardware volume works only in the analog > mode. Currently that means that PulseAudio's volume control has no > effect in the digital mode, because PulseAudio controls a mixer element > that doesn't do anything. > > I want to disable hardware volume for that card by default, because > that's the only safe default. That reduces the audio quality a bit, > however, so it would be good to allow concerned users to enable > hardware volume for the card without too much hassle. > > I'd like some feedback to guide the design: > > 0) Is this feature worth the maintenance burden the new code causes, or > should I just forget about this? (My answer: it's worth doing.) > > 1) Should the client API be specific to alsa, or should it be added to > the core interface? A third option exists too: don't make it specific > to alsa, but implement the client API in a module with a protocol > extension, and hook to the new module from alsa code. (My answer: > core.) > > 2) Should the hardware volume toggle be associated with a card or a > port or both? Associating it with the card would make the UI a bit > simpler. Logically, though, the toggle should be associated with a > port, because in the specific use case that I'm concentrating on the > volume problem concerns only the output path, not the input path. > There's no reason to disable hardware volume for the input path. > Whatever we choose, it's always possible to extend the code to support > both per-card and per-port toggles. (My answer: start with per-port.) > > [1] http://thread.gmane.org/gmane.comp.audio.pulseaudio.general/22253 > [2] http://thread.gmane.org/gmane.comp.audio.pulseaudio.general/23351 > [3] http://thread.gmane.org/gmane.comp.audio.pulseaudio.general/23434 > > -- > Tanu > _______________________________________________ > pulseaudio-discuss mailing list > pulseaudio-discuss at lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss
