Improved Battery Reporting For Newer Logitech Devices Coming To Linux 5.12

Newer wireless Logitech keyboard/mice supporting "unified battery" reporting will be supported beginning with Linux 5.12 as a newer interface compared to the existing battery reporting support.

While Logitech doesn't engage much with seeing good Linux support by their consumer devices (there has been only a handful of commits from Logitech developers over the past decade - in most cases providing just some basic bits), the open-source community through reverse engineering and widespread testing have filled in the voids. Wireless Logitech devices on Linux have generally enjoyed working battery reporting under Linux while now support for an interface found with newer devices is forthcoming.

The existing kernel support and what has been traditionally found with Logitech devices allows for exposing the critical / low / good / full battery reporting. But with the "unified battery" (0x1004) feature, a battery percentage can now be reported on newer devices. The newer devices can still end up in some cases supporting the old battery reporting functionality, but moving ahead with Linux 5.12+ if a battery percentage is available that is the preferred means of reporting to the user.

This patch for the hid-logitech-hidpp driver by Arch Linux developer Filipe Lains has been queued into the HID-next code ahead of Linux 5.12.