On Tue, Jan 17, 2023 at 04:17:23PM +0100, Bastien Nocera wrote: > Hey, > > TLDR: new sysfs attribute that makes it possible to leave receivers for > wireless headsets plugged in. At the USB level, or at the base driver > level? > > Longer version: > I started working on implementing support for some wireless headsets > that use USB receivers to communicate to the headset itself. Would this also include wireless keyboard/mice recievers? Why is "wireless" somehow a special attribute that userspace needs to know about? > The USB receivers have multiple interfaces, and independent drivers for > each, as is wont to do for USB devices. There's usually a HID interface > to do the custom stuff (LEDs, battery status, connection status, etc.) > and a standard audio class interface. This probably should be an interface attribute (as Alan points out), as it's not a device attribute (think about updating the firmware for one of these, that's on an interface for the reciever you plugged in, not on the other end of the wireless connection...) > Those drivers don't know anything about each other, and getting them to > talk to each other would be rather complicated. Additionally the audio > interface is still somewhat functional when the headset is > disconnected. Those drivers shouldn't know about each other, that's up to userspace to group and control if needed. No kernel interactions should be needed. > In the end, I came up with this new sysfs attribute that would make it > possible for user-space (PulseAudio or Pipewire) to know whether the > receiver is plugged in or not. Again, should be an interface attribute, if at all. > That allows user-space to not show the battery information for the > device (rather than 0 percent), not offer the headset as an output, and > potentially automatically switch to it when the headset is powered on. Same for a keyboard/mouse, right? thanks, greg k-h
