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=-13.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 0390FC5519F for ; Fri, 20 Nov 2020 09:21:29 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6C8452224C for ; Fri, 20 Nov 2020 09:21:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="i1YbwAly"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="XNqG64/n" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6C8452224C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=cZaXsmyB6q+HHsta5O3Ee7/fK1jFMdUznymSaWniY+o=; b=i1YbwAlyeSQSZWrW5mkTR1f3i dfexcOYCKoaWl45ZUTFDywSCTmUFZ4lEpmmdLaUByC3Nfb7rnpSCUhgarSUFSN9pp+t2stg3ywEDw R3O7f/JyJdWF/PL5+HaVrpj0CiUXhlOnhzdeaYiDlor1BRf6uicUWt+OYwDom+wobBTACcuHUTnKY eoErln83o2uLeNOcmBVj7jid4RpfbCHsmWjSY0s5yaIJWp0P0ems0vfOioYxJOgixRS2Yz8g/CmCZ ZJTRXoTyTh2yQYhEzXaQ0h7ZbtlqGpJt+J/dGiEhFAUiHo7y/juEP9sPj+eMjfDJjltTS+wtMsc6N 6uaXFmLyg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kg2bD-0007mg-W0; Fri, 20 Nov 2020 09:21:00 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kg2ah-0007br-L6; Fri, 20 Nov 2020 09:20:31 +0000 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E803922264; Fri, 20 Nov 2020 09:20:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1605864026; bh=2u/5mhCZv1xdPFL6xL5rON8rEuNwDZ5NL6N7lPUewns=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=XNqG64/n8KmjuhcLmgLYf48IecH4L16ozQdP/cgWyMIffoCtf5iL0LH+I73HgmXNg AqlemRpN+JQttIotgWDRxHQTUti6HwOpzRC+nLmEOqs0zr05ylBp/WNzt+TmLSEls+ z1Ti3DfpbibbsXvK+UXsqXlDwyD6HKA58gHvntmM= Date: Fri, 20 Nov 2020 10:20:58 +0100 From: Greg Kroah-Hartman To: Min Guo Subject: Re: [PATCH] usb: musb: remove unused variable 'devctl' Message-ID: References: <20201117082125.7619-1-min.guo@mediatek.com> <1605854930.3995.8.camel@mhfsdcap03> <1605858126.3995.14.camel@mhfsdcap03> <1605862935.3995.20.camel@mhfsdcap03> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1605862935.3995.20.camel@mhfsdcap03> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201120_042027_933587_E0AF34AD X-CRM114-Status: GOOD ( 34.90 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, chunfeng.yun@mediatek.com, linux-mediatek@lists.infradead.org, Matthias Brugger , Bin Liu , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Nov 20, 2020 at 05:02:15PM +0800, Min Guo wrote: > On Fri, 2020-11-20 at 09:36 +0100, Greg Kroah-Hartman wrote: > > On Fri, Nov 20, 2020 at 03:42:06PM +0800, Min Guo wrote: > > > On Fri, 2020-11-20 at 07:54 +0100, Greg Kroah-Hartman wrote: > > > > On Fri, Nov 20, 2020 at 02:48:50PM +0800, Min Guo wrote: > > > > > Hi greg k-h: > > > > > On Wed, 2020-11-18 at 12:48 +0100, Greg Kroah-Hartman wrote: > > > > > > On Tue, Nov 17, 2020 at 04:21:25PM +0800, min.guo@mediatek.com wrote: > > > > > > > From: Min Guo > > > > > > > > > > > > > > Remove unused 'devctl' variable to fix compile warnings: > > > > > > > > > > > > > > drivers/usb/musb/musbhsdma.c: In function 'dma_controller_irq': > > > > > > > drivers/usb/musb/musbhsdma.c:324:8: warning: variable 'devctl' set > > > > > > > but not used [-Wunused-but-set-variable] > > > > > > > > > > > > > > Signed-off-by: Min Guo > > > > > > > --- > > > > > > > drivers/usb/musb/musbhsdma.c | 4 ---- > > > > > > > 1 file changed, 4 deletions(-) > > > > > > > > > > > > > > diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c > > > > > > > index 0aacfc8be5a1..7acd1635850d 100644 > > > > > > > --- a/drivers/usb/musb/musbhsdma.c > > > > > > > +++ b/drivers/usb/musb/musbhsdma.c > > > > > > > @@ -321,8 +321,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data) > > > > > > > musb_channel->channel.status = > > > > > > > MUSB_DMA_STATUS_BUS_ABORT; > > > > > > > } else { > > > > > > > - u8 devctl; > > > > > > > - > > > > > > > addr = musb_read_hsdma_addr(mbase, > > > > > > > bchannel); > > > > > > > channel->actual_len = addr > > > > > > > @@ -336,8 +334,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data) > > > > > > > < musb_channel->len) ? > > > > > > > "=> reconfig 0" : "=> complete"); > > > > > > > > > > > > > > - devctl = musb_readb(mbase, MUSB_DEVCTL); > > > > > > > > > > > > Are you sure that the hardware does not require this read to complete > > > > > > the command? Lots of hardware is that way, so be very careful about > > > > > > this. Did you test it? > > > > > > > > > > I have tested this patch on Mediatek's platform, and not sure if it > > > > > will affect other vendors' platforms. > > > > > > > > > > Dear Bin: > > > > > > > > > > Does this patch will affect other vendors' platforms? > > > > > > > > The hardware specs will answer this question, what do they say about > > > > this read? > > > > > > Sorry, I didn't seen the comment on the hardware specs indicate that > > > devctl register needs to read once to take effect. > > > > Perhaps you might want to add a comment here so that people will not > > keep making this same mistake when they run auto-checkers on the > > codebase? > > Sorry for confused you, I searched the hardware specs, but did not find > the special description of the register devctl indicating that it needs > to be read out before the hardware can work. If this is a PCI device, that is implied as that is how all PCI devices work, right? What is the problem that is fixed by removing this read? thanks, greg k-h _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel