On Wed, 13 Jan 2021 16:03:39 +0100, Bastien Nocera wrote: > > On Wed, 2021-01-13 at 15:49 +0100, Takashi Iwai wrote: > > On Wed, 13 Jan 2021 15:36:19 +0100, > > Bastien Nocera wrote: > > > > > > Hey, > > > > > > On Wed, 2020-12-09 at 14:30 +0100, Bastien Nocera wrote: > > > > Hey, > > > > > > > > I've recently bought a SteelSeries Arctis 1 wireless headset: > > > > https://steelseries.com/gaming-headsets/arctis-1-wireless-xbox > > > > and wanted to write a kernel driver to export a few features of > > > > the > > > > device, and needed some help getting started. > > > > > > > > The receiver shows up as a audio class USB device, with extra > > > > features > > > > on a separate USB interface.[1] > > > > > > > > The extra features that can be accessed are: > > > > - Presence detection. I wanted to use that so PulseAudio or > > > > Pipewire > > > > could make routing decisions based on whether the headset is > > > > available, > > > > or probably better, implementing a "jack detection" emulation for > > > > the > > > > main audio interface? > > > > - A slider to change the sidetone volume > > > > - Export the battery level > > > > > > > > The latter is the only one I know how to do, so I'd be happy with > > > > any > > > > pointers or examples about the first two items. > > > > > > > > > I sent this in December and didn't get any answers, and I would > > > appreciate any guidance/examples if you have any into implementing > > > this. > > > > Judging from the link, is it controlled through HID? If so, it's > > primarily done by a HID driver, and it doesn't belong to the sound > > card stuff, so far. > > Though.... > > > > > I would imagine that the new features would be implemented through > > > a > > > separate ALSA device with few features, which PulseAudio/Pipewire > > > could > > > merge with the existing USB audio device. > > > > ... given that it's implemented in a HID driver, the integration to > > the system is a different question. But unless it's implemented as a > > sound card device, the rest will become a totally different, > > e.g. another PA or PW module. > > I think that it might be good to have the sidetone configuration > implemented as a channel mixer, so it could be shown along with the > device volume in sound settings. > > I believe there's already a device group feature in PulseAudio that > could be used to merge the sidetone level with the rest of the USB > audio mixers. > > Is there an example of a mixer like that implemented in a hid or > another type of non-ALSA/sound driver? Nothing so far, and that's the problem. HID is managed in a completely different layer, hence the integration needs to be done in a higher level like PA, I suppose. In theory we might be able to extend UCM to handle the other external devices, though. Takashi
