From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7FDC9C7EE2F for ; Thu, 2 Mar 2023 15:27:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229871AbjCBP16 (ORCPT ); Thu, 2 Mar 2023 10:27:58 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58178 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229720AbjCBP1k (ORCPT ); Thu, 2 Mar 2023 10:27:40 -0500 Received: from netrider.rowland.org (netrider.rowland.org [192.131.102.5]) by lindbergh.monkeyblade.net (Postfix) with SMTP id 0D08330EA9 for ; Thu, 2 Mar 2023 07:27:38 -0800 (PST) Received: (qmail 251323 invoked by uid 1000); 2 Mar 2023 10:27:38 -0500 Date: Thu, 2 Mar 2023 10:27:38 -0500 From: Alan Stern To: Bastien Nocera Cc: linux-usb@vger.kernel.org, linux-input@vger.kernel.org, Greg Kroah-Hartman , Benjamin Tissoires , Filipe =?iso-8859-1?Q?La=EDns?= , Nestor Lopez Casado Subject: Re: [PATCH v3 4/6] USB: core: Add wireless_status sysfs attribute Message-ID: References: <20230302105555.51417-1-hadess@hadess.net> <20230302105555.51417-4-hadess@hadess.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20230302105555.51417-4-hadess@hadess.net> Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org On Thu, Mar 02, 2023 at 11:55:53AM +0100, Bastien Nocera wrote: > Add a wireless_status sysfs attribute to USB devices to keep track of > whether a USB device that's comprised of a receiver dongle and an emitter > device over a, most of the time proprietary, wireless link has its emitter > connected or disconnected. > > This will be used by user-space OS components to determine whether the > battery-powered part of the device is wirelessly connected or not, > allowing, for example: > - upower to hide the battery for devices where the device is turned off > but the receiver plugged in, rather than showing 0%, or other values > that could be confusing to users > - Pipewire to hide a headset from the list of possible inputs or outputs > or route audio appropriately if the headset is suddenly turned off, or > turned on > - libinput to determine whether a keyboard or mouse is present when its > receiver is plugged in. > > This is done at the USB interface level as: > - the interface on which the wireless status is detected is sometimes > not the same as where it could be consumed (eg. the audio interface > on a headset dongle will still appear even if the headset is turned > off), and we cannot have synchronisation of status across subsystems. > - this behaviour is not specific to HID devices, even if the protocols > used to determine whether or not the remote device is connected can > be HID. > > This is not an attribute that is meant to replace protocol specific > APIs, such as the ones available for WWAN, WLAN/Wi-Fi, or Bluetooth > or any other sort of networking, but solely for wireless devices with > an ad-hoc “lose it and your device is e-waste” receiver dongle. > > The USB interface will only be exporting the wireless_status sysfs > attribute if it gets set through the API exported in the next commit. > > Signed-off-by: Bastien Nocera > --- For parts 4 and 5: Acked-by: Alan Stern