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 A1439C352A1 for ; Tue, 6 Dec 2022 10:00:17 +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=LXDbkX8kKhoquNzaP2oip67Mb5+vJeM4BnZWs6U03gw=; b=O5SgDg9yLPBwik 3pkyELi07LqY8iuHb7k1tiJre/d3IKrsb/j/l7Pm0SXIiitXbDCdjQsIkvpmK+W9c0VB415G/kLCE gPAlKuprUMggwhMdDejoYb0E+8BGRl32JM23eCiL1B+OVZ241TNJRl6ERroHojNCvzoT3Qc3Zgg7a 2/4hrjuV2QwkWFxRv0kViXh8mZOzoqHeT/F21gMxdpANGK0qBXm9/d1u2vcHGD/7eqrt3lcqEFO7w 5RmcAXFQ6JovnSO/19PJPZGxHFJVt5YpAqJqlDSVZdJIb3kllCVpv7u5ME/VBEVUlaZD1wgFmVOhq 1ikeM+YMD/fNqDUuYGNA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1p2Uj4-006Z4w-74; Tue, 06 Dec 2022 09:58:58 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1p2Uib-006YlQ-17 for linux-arm-kernel@lists.infradead.org; Tue, 06 Dec 2022 09:58:30 +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 4656C615FE; Tue, 6 Dec 2022 09:58:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6D036C433C1; Tue, 6 Dec 2022 09:58:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1670320707; bh=8eqYHz5ExDaNpGaZCWZ0BLnEDa7J4gSmHd03xoUp1Xk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Onaw83TaPGAyrDp68Tci0OAb6La21Jx+cUkzFLWP47/DJDgG/CWU/Hwp13UkjL3Ca Ve4Ej6GW43twSsoc2eiLyupj8YSiiBWgG4Jc2bG/AaMZ7Rd7bIwi31pd5GacpNiPPy f3Ol8d8W/ckIlCIl6ZJxCDLSygoYZHNoBHKpdUxt3SEKst3ck64OFyWi3GYZwd8ph5 v6NEN3gmj6Z1xUkVsyMVJwaRzcOm4iKjmhV4TQxPf/qv3dIRAJVtzNNkO02fvycCeK VzsBy6/r5XcS9h0sVukfbnGPvtDIe+Ba5/G5658Tofn0xT504L7zxRgKImuqRQ7i3F kdt9/cxyVuZfA== Date: Tue, 6 Dec 2022 09:58:21 +0000 From: Will Deacon To: Manivannan Sadhasivam Cc: Greg KH , Thorsten Leemhuis , Amit Pundir , Catalin Marinas , Sibi Sankar , 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: <20221206095820.GB317@willie-the-truck> References: <20221202100357.GB29396@willie-the-truck> <92a148a3-a8ac-4065-123c-99b72ac3ebeb@leemhuis.info> <395ad6ef-eb54-ec7e-e131-714f23c84d7a@leemhuis.info> <20221202171437.GH5356@thinkpad> <20221205142402.GA31783@willie-the-truck> <20221206092152.GD15486@thinkpad> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20221206092152.GD15486@thinkpad> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221206_015829_186125_5C50C9B6 X-CRM114-Status: GOOD ( 44.01 ) 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 Tue, Dec 06, 2022 at 02:51:52PM +0530, Manivannan Sadhasivam wrote: > On Mon, Dec 05, 2022 at 02:24:03PM +0000, Will Deacon wrote: > > On Fri, Dec 02, 2022 at 10:44:37PM +0530, Manivannan Sadhasivam wrote: > > > On Fri, Dec 02, 2022 at 05:32:51PM +0100, Greg KH wrote: > > > > 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? > > > > > > > > > > It is the Qualcomm Q6V5_MSS remoteproc driver: > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/remoteproc/qcom_q6v5_mss.c > > > > > > Qualcomm is working on the fix but the patches are not ready yet. So if we can > > > get this patch reverted in the meantime, that would be helpful. > > > > It's good to hear that you're working to fix this, even if it's happening > > behind closed doors. Do you have a rough idea how soon you'll be able to > > post the remoteproc driver fixes? That would help us to figure out when > > to bring back the change if we were to revert it. > > > > Sibi is the one working on the fix. I believe he should be able to post the > patches within this week. Oh nice, that's a lot sooner than I expected! I'll send a revert out now, with a comment about where we're at. Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel