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 2DB16C4321E for ; Mon, 5 Dec 2022 14:25:22 +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=yyCtRoUYYf5I1mOj9Llu9hSMyX55EmyYPF1ulD/AnaY=; b=g2pK3BFcqSlWsS 1yAhCWTJEtJVF3ym/lz0c3GCCgLJS1Ti7SpXrD7J2zlTvUOH3f0jtB+VdgYSBcy42KlpfkoWAP9gY BCF8ADAexE/EfAa/27eqKox9ihka9T/SrOV5B3Z0l7AIII1Aaurq/9J8Rst8mryyb3HeBZF8vqMau EdwQ1r41ys6/NOEeZaoi67NLLzQjI68ALiomIBhQmomP65o1+CmmsHqggqsq/HYk9k0Tm34HC/rTt o3801L5qHvsXegMz8BxLp2vhSAknBIwmOXENSKDtv/2OPtya4thG4ckEs0ff4PXaeP5jI9kuP8F2Y Wvy8Mc1ov9bcZk6uofHw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1p2COJ-0042qA-P3; Mon, 05 Dec 2022 14:24:20 +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 1p2COB-0042l8-IF for linux-arm-kernel@lists.infradead.org; Mon, 05 Dec 2022 14:24:14 +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 5B6496117E; Mon, 5 Dec 2022 14:24:09 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B1D42C433C1; Mon, 5 Dec 2022 14:24:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1670250249; bh=Ga1etePyywTh7KmP0kVhAXuTI89MxsurxbY+ShnzFMA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=uBS5OGYjBDCqLhKn2ikLcA3iPA78DIFQIx1ERbXTm8VxByd90B77rdrQZYlsXDqyz fIhV0GHswf8xkdaneiwAyYows42xJfmAAC0/CWORW7kJRCfK2hEJn4XCmb0U9HXEXk YUIlwB12B7xzFjdLHlXtelUYw6XeIeZupZzLJGKymtPAwCjIZc9A65G7xcoXTsmhoK ff/RrGZ9d9ZHPpAkr4QbrgWtUIbIXEGVGEG8aglQJJYlAzk9+ttVOVGNqaolrUmf3j eAtFzbkJolHQ61YBYdtX8L06Nixc31ZnYUw/YDzlGilk7kfAVwqELccK/XRcOHh1hm Va4mFquebUqMw== Date: Mon, 5 Dec 2022 14:24:03 +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: <20221205142402.GA31783@willie-the-truck> References: <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> <20221202171437.GH5356@thinkpad> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20221202171437.GH5356@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-20221205_062411_727460_63A5ADF8 X-CRM114-Status: GOOD ( 38.63 ) 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 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. Cheers, Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel