On Fri, Mar 23, 2018 at 12:47 AM, Takashi Iwai <tiwai@xxxxxxx> wrote: > Let's follow the other usages, and here iface is set to > SNDRV_CTL_ELEM_IFACE_CARD. This was for avoiding such volatile > controls appearing the mixer application. Will do - it looks like the "Clock Source Validity" control also needs this. I'll send a patch for that as well. >> + .access = SNDRV_CTL_ELEM_ACCESS_READ, > > Actually we should have set SNDRV_CTL_ELEM_ACCESS_VOLATILE, too. > We forgot it in ctljack.c, too. Sounds good. > > The rest looks good. But one thing to confirm: the value change > notification is done in snd_usb_mixer_interrupt()? > > Also, is the jack re-detected after suspend/resume? That is, plug off > the jack while sleeping, and after the resume, is the jack status > change recognized and notified? Yes - the USB audio device causes a remote wakeup, then after a few ms responds with the interrupt data message indicating the connector control that changed. This ends up calling snd_usb_mixer_interrupt(). On codeaurora kernels for Qualcomm SoCs, there's a patch which enables autosuspend for any USB device with an audio interface. https://source.codeaurora.org/quic/la/kernel/msm-4.4/tree/sound/usb/card.c?h=LA.HB.1.1.5.c1#n663 so suspend/resume paths are well tested when devices are used on Android. Two new questions: #1 - I'd like to report the impedance of the load connected to the jack (generally as an integer). Is a read-only control element the right way to do this? #2 - In our particular case there's a single jack which can detect presence of a microphone and playback separately. USB descriptors provide a mechanism to show that the input and output terminals are linked in this way (terminal type 4xx along with bAssocTerminal). Is there a better way of having this reported than two separate mono jack controls? _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
