On Mon, 11 Dec 2017 13:30:35 +0100, Hans de Goede wrote: > > Hi All, > > This weekend I've created a modified ucm config based on: > > https://github.com/plbossart/UCM/tree/master/chtrt5645 > > For a board which has a single speaker connected to the > left channel (standard mono speaker setup) and a stereo > headphone jack with working jack detection. > > I've been unable to come up with a ucm file which allows > selecting between a "Stereo Speaker + Headphone" vs > "Mono Speaker + Headphone" output profile. > > https://github.com/plbossart/UCM/tree/master/byt-rt5640 > has "Mono Speaker", "Stereo Speaker" and "Headphone" > profiles but does not auto-switch between Headphone > and speaker based on jack detection, I've been unable to > allow selecting either stereo or mono speaker while > keeping auto-switching to/from the headphones. > > But thinking more about this I don't think that having > "Stereo Speaker + Headphone" and "Mono Speaker + Headphone" > profiles is the answer. Profiles make sense on machines with > a bunch of outputs where we don't no what the user is going > to plug in, but in this case the stereo vs mono speaker > distinction is a clear property of the device, which we > should IMHO autodetect based on the device-model. > > So I think we need a way to have different ucm files per board, > so instead of loading /usr/share/ucm/chtrt5645/*.conf on my > device, alsa should try to load /usr/share/ucm/chtrt5645-<boardname>/*.conf > > Specifically I'm thinking about using udev + hwdb (dmi string) > matching to set an ALSA_UCM_NAME udev property. > > If the consensus is that this is a good idea I can take a shot > at writing patches for this (in my spare time mostly), the > downside of this approach is it would cause a dependency on > libudev for the alsa ucm code. You don't need to patch, I guess. The recent code should set a string generated from DMI as the longname of the card, and alsa-lib UCM parser prefers the longname to the driver name field. That is, /usr/share/ucm/$LONGNAME/$LONGNAME.conf would be read at first, then /usr/share/ucm/$DRIVER/$DRIVER.conf is used as fallback. Takashi
