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 X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F37C5C38A2A for ; Sat, 9 May 2020 03:24:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CDF9E217BA for ; Sat, 9 May 2020 03:24:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728614AbgEIDYM (ORCPT ); Fri, 8 May 2020 23:24:12 -0400 Received: from out30-43.freemail.mail.aliyun.com ([115.124.30.43]:37030 "EHLO out30-43.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728355AbgEIDYL (ORCPT ); Fri, 8 May 2020 23:24:11 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R191e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01f04397;MF=wenyang@linux.alibaba.com;NM=1;PH=DS;RN=9;SR=0;TI=SMTPD_---0Txzw3bb_1588994648; Received: from IT-C02W23QPG8WN.local(mailfrom:wenyang@linux.alibaba.com fp:SMTPD_---0Txzw3bb_1588994648) by smtp.aliyun-inc.com(127.0.0.1); Sat, 09 May 2020 11:24:08 +0800 Subject: Re: [PATCH] usb: roles: Switch on role-switch uevent reporting To: Bryan O'Donoghue , heikki.krogerus@linux.intel.com, gregkh@linuxfoundation.org, linux-usb@vger.kernel.org Cc: Chunfeng Yun , Suzuki K Poulose , Alexandre Belloni , chenqiwu , linux-kernel@vger.kernel.org References: <20200508162937.2566818-1-bryan.odonoghue@linaro.org> From: Wen Yang Message-ID: Date: Sat, 9 May 2020 11:24:08 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:68.0) Gecko/20100101 Thunderbird/68.1.0 MIME-Version: 1.0 In-Reply-To: <20200508162937.2566818-1-bryan.odonoghue@linaro.org> Content-Type: text/plain; charset=gbk; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ÔÚ 2020/5/9 ÉÏÎç12:29, Bryan O'Donoghue дµÀ: > Right now we don't report to user-space a role switch when doing a > usb_role_switch_set_role() despite having registered the uevent callbacks. > > This patch switches on the notifications allowing user-space to see > role-switch change notifications and subsequently determine the current > controller data-role. > > example: > PFX=/devices/platform/soc/78d9000.usb/ci_hdrc.0 > > root@somebox# udevadm monitor -p > > KERNEL[49.894994] change $PFX/usb_role/ci_hdrc.0-role-switch (usb_role) > ACTION=change > DEVPATH=$PFX/usb_role/ci_hdrc.0-role-switch > SUBSYSTEM=usb_role > DEVTYPE=usb_role_switch > USB_ROLE_SWITCH=ci_hdrc.0-role-switch > SEQNUM=2432 > > Cc: Heikki Krogerus > Cc: Greg Kroah-Hartman > Cc: Chunfeng Yun > Cc: Suzuki K Poulose > Cc: Alexandre Belloni > Cc: Wen Yang > Cc: chenqiwu > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Bryan O'Donoghue > --- > drivers/usb/roles/class.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c > index 5b17709821df..27d92af29635 100644 > --- a/drivers/usb/roles/class.c > +++ b/drivers/usb/roles/class.c > @@ -49,8 +49,10 @@ int usb_role_switch_set_role(struct usb_role_switch *sw, enum usb_role role) > mutex_lock(&sw->lock); > > ret = sw->set(sw, role); > - if (!ret) > + if (!ret) { > sw->role = role; > + kobject_uevent(&sw->dev.kobj, KOBJ_CHANGE); > + } > > mutex_unlock(&sw->lock); > > Hi, we may also need to deal with the return value of kobject_uevent(). Should we move it under the line mutex_unlock(&sw->lock)? Regards, Wen