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=-5.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, USER_AGENT_MUTT 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 A4423C43381 for ; Tue, 26 Feb 2019 16:39:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 716942184D for ; Tue, 26 Feb 2019 16:39:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551199192; bh=lcwJmi+mbC/puoxwL6ouKhjYjp327Z2coyGiJttKJ2c=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=eON3n7bSyCbrIoVMPg8RFJgCSBNpo+QmSk//4HwluT2D5GtHBbtVv4YXYPV7eAOnr jTat6hfXaJ0mh+N7COU8M0QBDmsHBX/kTBpWRsyqqCN8VVhHSUxWUK15vfKwyiOxkR Ey9j2mqjc+ai3Jbgges+bXW8MrQ27wmwgRV3RGMI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728568AbfBZQjv (ORCPT ); Tue, 26 Feb 2019 11:39:51 -0500 Received: from mail-ot1-f66.google.com ([209.85.210.66]:40458 "EHLO mail-ot1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727054AbfBZQju (ORCPT ); Tue, 26 Feb 2019 11:39:50 -0500 Received: by mail-ot1-f66.google.com with SMTP id v20so11625974otk.7; Tue, 26 Feb 2019 08:39:50 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=cMT88YQQfyXIgu4kn+RVboLvqoRCCLw3kepgIJfJrq8=; b=ESZK3O0t98A2/CEK/piD4qjJ/E+jidKkx039uXYk9rJbZQFuXn9yh0G4sMb5bdEAAz yQE5qoYuCBU3Gumtj/oiL5Ls2O9ftcU84ol8Hhw5TYlkpg0KKOUQoKrPZCcpbm+VQhv8 zSFbBL24l0ZKcXLj6YjJ4yemQWBXiYrhBn1CmoPq1Fin2QGg8v+ksXP1fERMg6r7b+3f Nk0WjjvM0gs+CPxYWL1G60JQsYXlHU4Ob6+NgA5bCFIdZNnTZRNyz1MuSet1+pgCmnqM HvEbT5rMsTqqF4YHO3VCXXqkHeO+zakQsrbOjY+ugTtOw7CedQoQTESOTEFog3E/okbZ nfJw== X-Gm-Message-State: AHQUAuZPllbfeaJ/uajS4D17dhAy1FVnraB0Jpjqv2QExF623XtKISHr P4CJDPz4pGgnbptdr6OP8YlLZ8w= X-Google-Smtp-Source: AHgI3IYYsd3s1omOgAVurathtKI24siCJUkO0pB8AksCs175SuHSWgNFvkXLYYO1OeNxvsmW6EnBlg== X-Received: by 2002:a9d:4c02:: with SMTP id l2mr15855630otf.56.1551199189701; Tue, 26 Feb 2019 08:39:49 -0800 (PST) Received: from localhost (24-155-109-49.dyn.grandenetworks.net. [24.155.109.49]) by smtp.gmail.com with ESMTPSA id y37sm6061269ota.17.2019.02.26.08.39.48 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 26 Feb 2019 08:39:48 -0800 (PST) Date: Tue, 26 Feb 2019 10:39:48 -0600 From: Rob Herring To: Ran Wang Cc: Greg Kroah-Hartman , Yang Li , "linux-usb@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Ran Wang Subject: Re: [PATCH v3 1/2] usb: dwc3: Add avoiding vbus glitch happen during xhci reset Message-ID: <20190226163948.GA8854@bogus> References: <20190226070016.27372-1-ran.wang_1@nxp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190226070016.27372-1-ran.wang_1@nxp.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 26 Feb 2019 06:59:21 +0000, Ran Wang wrote: > When DWC3 is set to host mode by programming register DWC3_GCTL, VBUS > (or its control signal) will turn on immediately on related Root Hub > ports. Then the VBUS will be de-asserted for a little while during xhci > reset (conducted by xhci driver) for a little while and back to normal. > > This VBUS glitch might cause some USB devices emuration fail if kernel > boot with them connected. One SW workaround which can fix this is to > program all PORTSC[PP] to 0 to turn off VBUS immediately after setting > host mode in DWC3 driver(per signal measurement result, it will be too > late to do it in xhci-plat.c or xhci.c). > > Signed-off-by: Ran Wang > --- > Changes in v3: > - None > > Changes in v2: > - Correct typos > - Shorten the name to snps,host-vbus-glitches > > Documentation/devicetree/bindings/usb/dwc3.txt | 3 +++ > 1 files changed, 3 insertions(+), 0 deletions(-) > Please add Acked-by/Reviewed-by tags when posting new versions. However, there's no need to repost patches *only* to add the tags. The upstream maintainer will do that for acks received on the version they apply. If a tag was not added on purpose, please state why and what changed.