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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B5C61C4321E for ; Fri, 2 Dec 2022 16:34:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc: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=GAXAe+z+r78WEyq3bgcQ/ab0Mnajk9WNXgvGU5zx7/w=; b=0soQ/luIyMQlkE RzfCN+r8vrGEMnTu8eZGBSDe+04Gr2PA5bIrEevtGBdrAyQ4KzSEUDv6+3CyDKFzwN5fMXd7sZaqt n9II4TNE0iq+Fm4ENhcjMACwOX+hky9pFK9mh5vDXbmn8lo4Assyek5F60Z/go0WiEH/jpK3zXjjn y8vBB/1KGurabJkKepZOmOnSh3fr3Mrhkri06Z4b9Iag3WfvxyYYID7SOiolRSU/RGZg17xsqX/pT 8sD0iO5rdbOEs2Td+9nYbUYx9T5ng0TYkko6v26zWw/RrAVOxgiuS7LK0Pp9vO9tHx4Z1iaa72PNE loJlWKLHIwigACW6+WLg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1p18yD-00HZkW-AS; Fri, 02 Dec 2022 16:33:02 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1p18y8-00HZic-7y for linux-arm-kernel@lists.infradead.org; Fri, 02 Dec 2022 16:32:58 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 105C062337; Fri, 2 Dec 2022 16:32:55 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EF39AC433D6; Fri, 2 Dec 2022 16:32:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1669998774; bh=pQ7g0nDMOMcY6daJmycAqY67TFIHNGmsVxECzKIRMaE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=1s3wulxVdXIVq63bb87WUMUUL+XldGTyL7zWeuy5CHBc6+Xspp0QWBY2C5xcWatCl 88nRgRjSA9XlLB0ROROfY4ObT2oVdXFa2PfqLdv2SaUZj7ufAVg7d0eiVPBw9d7gB9 45ZkQaeX5l/ZydAUSGRq8i0AvssFWLnFfapK05P4= Date: Fri, 2 Dec 2022 17:32:51 +0100 From: Greg KH To: Thorsten Leemhuis Cc: Will Deacon , Amit Pundir , Catalin Marinas , Sibi Sankar , Manivannan Sadhasivam , Robin Murphy , andersson@kernel.org, sumit.semwal@linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, hch@lst.de Subject: Re: [PATCH] Revert "arm64: dma: Drop cache invalidation from arch_dma_prep_coherent()" Message-ID: References: <018517b8-0ae0-54f5-f342-dcf1b3330a13@quicinc.com> <6d637906-e1d5-c481-a73d-2b2b845e223b@leemhuis.info> <20221202100357.GB29396@willie-the-truck> <92a148a3-a8ac-4065-123c-99b72ac3ebeb@leemhuis.info> <395ad6ef-eb54-ec7e-e131-714f23c84d7a@leemhuis.info> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <395ad6ef-eb54-ec7e-e131-714f23c84d7a@leemhuis.info> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221202_083256_414866_6A89F664 X-CRM114-Status: GOOD ( 28.14 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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, Dec 02, 2022 at 05:27:24PM +0100, Thorsten Leemhuis wrote: > > > On 02.12.22 17:10, Greg KH wrote: > > On Fri, Dec 02, 2022 at 11:34:30AM +0100, Thorsten Leemhuis wrote: > >> On 02.12.22 11:03, Will Deacon wrote: > >>> On Fri, Dec 02, 2022 at 09:54:05AM +0100, Thorsten Leemhuis wrote: > >>>> On 02.12.22 09:26, Amit Pundir wrote: > >>>>> On Thu, 1 Dec 2022 at 23:15, Catalin Marinas wrote: > >>>>>> > >>>>>> On Thu, Dec 01, 2022 at 10:29:39AM +0100, Thorsten Leemhuis wrote: > >>>>>>> Has any progress been made to fix this regression? It afaics is not a > >>>>>>> release critical issue, but well, it still would be nice to get this > >>>>>>> fixed before 6.1 is released. > >>>>>> > >>>>>> The only (nearly) risk-free "fix" for 6.1 would be to revert the commit > >>>>>> that exposed the driver bug. It doesn't fix the actual bug, it only > >>>>>> makes it less likely to happen. > >>>>>> > >>>>>> I like the original commit removing the cache invalidation as it shows > >>>>>> drivers not behaving properly > >>>> > >>>> Yeah, I understand that, but I guess it's my job to ask at this point: > >>>> "is continuing to live with the old behavior for one or two more cycles" > >>>> that much of a problem"? > >>> > >>> That wouldn't be a problem. The problem is that I haven't see any efforts > >>> from the Qualcomm side to actually fix the drivers [...] > >> > >> Thx for sharing the details. I can fully understand your pain. But well, > >> in the end it looks to me like this commit it intentionally breaking > >> something that used to work -- which to my understanding of the "no > >> regression rule" is not okay, even if things only worked by chance and > >> not flawless. > > > > "no regressions" for userspace code, this is broken, out-of-tree driver > > code, right? > > If so: apologies. But that's not the impression I got, as Amit wrote "I > can reproduce this crash on vanilla v6.1-rc1 as well with no out-of-tree > drivers." here: > https://lore.kernel.org/linux-arm-kernel/CAMi1Hd3H2k1J8hJ6e-Miy5+nVDNzv6qQ3nN-9929B0GbHJkXEg@mail.gmail.com/ Ah, I missed that. Ok, what in-tree drivers are having problems being buggy? I can't seem to figure that out from that report at all. Does anyone know? thanks, greg k-h _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel