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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D3A3FC352A1 for ; Tue, 6 Dec 2022 09:24:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234829AbiLFJYR (ORCPT ); Tue, 6 Dec 2022 04:24:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40184 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235055AbiLFJXu (ORCPT ); Tue, 6 Dec 2022 04:23:50 -0500 Received: from mail-pj1-x102d.google.com (mail-pj1-x102d.google.com [IPv6:2607:f8b0:4864:20::102d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8D36E20F41 for ; Tue, 6 Dec 2022 01:21:59 -0800 (PST) Received: by mail-pj1-x102d.google.com with SMTP id b11so13860543pjp.2 for ; Tue, 06 Dec 2022 01:21:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:from:to :cc:subject:date:message-id:reply-to; bh=37i4PLhbvOixYkzJrk3nfK3Vs02mt4pjFCyGYhE/6yw=; b=bd2kgLbTRBfKMhrHPs+EtDK3iSVQ7Hb/AsOw0eqpX1g6kfVd33s1+fpQx4UJ/GC0VT nHsQEPkielwsNM2G9ZWPwYoXqOkZD+E9lrXmZcZ/rLVPO6ksAV9k5nQ3jaLUbx6fzI0T PLmRlDChnPWj0wkjBVGYiFKYevIpoflU2f2k3CphvcQS0e1HyxPI4MLoBcYAGf5N4ait 4fQyfD7mj4DREW20VMbftjq+/Ab2uXyYtoI084nuzdLQTkMgtFE9AtFxmumazHTWr0Bi AtBuU+/n8TnQvQgVI4RRk2y4h0GPKzmaOw/D7VuHFd3nBPuemFI0TEOU+7Fr6F4TaiLj qVYA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=37i4PLhbvOixYkzJrk3nfK3Vs02mt4pjFCyGYhE/6yw=; b=NgfrXUp8lTYkC6VTKBUhzT7oRjv8HQL86aW5XrhwZQJO9AmTgKLkLSh5a5VXeDXiQH ZLEmZ8NXpifN8v2KJzIqTdeMWnZB2I/fOPS1pX/9Jo6T6pOaxTlUUihpF24Eaj+acvks l/vRWpZu4LtPnBZ6mOSxDTP8lKAdSk7Ld6eiSdsbpgmVHxoHbdHIX7IyKJqLthBDshws 7+aPMHEkMhFNQ4Wg2mWrvZ5gMtaQw6qFzjEilhklRJUCCrqiBVxwRiAsaqEBW+A/3PvZ CvI5MVb9+2IXbf9gH/gTaqK6usHlT6MMefHpTsrWYTbJHQGntFNVaRokvdIXakVYMgls Jclw== X-Gm-Message-State: ANoB5pmu9tOV0110z3UpsC09Wl+sVNs9eFY6VWS6jn7zu1h93RhJmjpU qTxuboA+Ix5DRwvisDqBw4D/ X-Google-Smtp-Source: AA0mqf450XD3p4pvvnhWO0oR2aiyvMsnhY2p+vYqQxKwKPZhZQ+tB+itI0bN2tbzOP7VC0mY1kON9w== X-Received: by 2002:a17:90b:3011:b0:219:5f5a:7192 with SMTP id hg17-20020a17090b301100b002195f5a7192mr33374737pjb.144.1670318518914; Tue, 06 Dec 2022 01:21:58 -0800 (PST) Received: from thinkpad ([59.92.103.18]) by smtp.gmail.com with ESMTPSA id 12-20020a170902c10c00b001869f2120a4sm12053483pli.94.2022.12.06.01.21.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 06 Dec 2022 01:21:57 -0800 (PST) Date: Tue, 6 Dec 2022 14:51:52 +0530 From: Manivannan Sadhasivam To: Will Deacon 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: <20221206092152.GD15486@thinkpad> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20221205142402.GA31783@willie-the-truck> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Thanks, Mani > Cheers, > > Will -- மணிவண்ணன் சதாசிவம்