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 7DE40C433EF for ; Wed, 4 May 2022 18:24:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245733AbiEDS2A (ORCPT ); Wed, 4 May 2022 14:28:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50746 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1376767AbiEDS1o (ORCPT ); Wed, 4 May 2022 14:27:44 -0400 Received: from netrider.rowland.org (netrider.rowland.org [192.131.102.5]) by lindbergh.monkeyblade.net (Postfix) with SMTP id BE774B0A59 for ; Wed, 4 May 2022 10:54:09 -0700 (PDT) Received: (qmail 1131655 invoked by uid 1000); 4 May 2022 13:54:08 -0400 Date: Wed, 4 May 2022 13:54:08 -0400 From: Alan Stern To: Jose Ignacio Tornos Martinez Cc: gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, marcel@holtmann.org Subject: Re: [PATCH v5] USB: core: skip unconfiguration if device doesn't support it Message-ID: References: <20220504151647.471885-1-jtornosm@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220504151647.471885-1-jtornosm@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Wed, May 04, 2022 at 05:16:47PM +0200, Jose Ignacio Tornos Martinez wrote: > Some devices like Bluetooth Dongles with CSR chip (i.e. USB > Bluetooth V4.0 Dongle by Trust) hang when they are unbound from > 'unbind' sysfs entry and can not be bound again. > > For these devices, CSR chip hangs when usb configuration command > with index 0 (used to unconfigure) is sent during disconnection. > > To avoid this unwanted result, it is necessary not to send this > command, so a new quirk has been created. By default, quirk is > not applied for any device and needs to be enabled by user. > > For these devices, athough device is not unconfigured, it is > better to avoid device hanging to be able to operate. Even > bluetooth can be previously turned off. > On the other hand, this is not important if usb device is going to > be bound again (normal behavior), i.e. with usbip. > > Signed-off-by: Jose Ignacio Tornos Martinez > --- Acked-by: Alan Stern