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[2620:137:e000::1:20]) by mx.google.com with ESMTP id pk18-20020a170906d7b200b0099bca252ee8si2652730ejb.961.2023.07.28.07.16.19; Fri, 28 Jul 2023 07:16:44 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=k20201202 header.b="OjskhXK/"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236853AbjG1Nji (ORCPT + 99 others); Fri, 28 Jul 2023 09:39:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53636 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236095AbjG1Njf (ORCPT ); Fri, 28 Jul 2023 09:39:35 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 58E1E3C04; Fri, 28 Jul 2023 06:39:34 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id C71E562130; Fri, 28 Jul 2023 13:39:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B4594C433C8; Fri, 28 Jul 2023 13:39:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690551573; bh=rrMGRA9QOCHjw1OjWOTAoukKaG1CWaZCt3LhiwC5Xp4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=OjskhXK/XxIHWmQ9Eh3vvEj0LiRtA3ng9FnPdhSzB65+LA4adEbSDS0tKNBed2fGY RN2kz3EgmIG3ZzLtKuDVgvjTzFQ9KAcuhqp2/qNdtUKmQlJphX2ZK6JDx2dVnFT0BK BNsrSPixeMUqEo27ztvE2KEfA3/9l463614d2vX8+GqL9U6wz/c+TNqldrzC97YCXS /EIr5sT9HKw/Rqk1pLHw2T+jZ/9Us+SP2r8q8HCKFsnN/GHTXTelAXTQPVFcu1K94k hBqHbmjZ8e2nOs0M6lumvF6JWfqaTIc5w8vNmKpWys2iC/5eT8F2PFnN/mMCVutNKd 7Zw6uRHBGOaQg== Date: Fri, 28 Jul 2023 14:39:27 +0100 From: Will Deacon To: Shuai Xue Cc: Bjorn Helgaas , Jonathan Cameron , chengyou@linux.alibaba.com, kaishen@linux.alibaba.com, yangyicong@huawei.com, baolin.wang@linux.alibaba.com, robin.murphy@arm.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org, rdunlap@infradead.org, mark.rutland@arm.com, zhuo.song@linux.alibaba.com Subject: Re: [PATCH v6 0/4] drivers/perf: add Synopsys DesignWare PCIe PMU driver support Message-ID: <20230728133926.GC21394@willie-the-truck> References: <20230725205955.GA665326@bhelgaas> <634f4762-cf2e-4535-f369-4032d65093f0@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <634f4762-cf2e-4535-f369-4032d65093f0@linux.alibaba.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Spam-Status: No, score=-7.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_HI, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 27, 2023 at 11:45:22AM +0800, Shuai Xue wrote: > > > On 2023/7/26 04:59, Bjorn Helgaas wrote: > > On Mon, Jul 24, 2023 at 10:18:07AM +0100, Jonathan Cameron wrote: > >> On Mon, 24 Jul 2023 10:34:08 +0800 > >> Shuai Xue wrote: > >>> On 2023/7/10 20:04, Shuai Xue wrote: > >>>> On 2023/6/16 16:39, Shuai Xue wrote: > >>>>> On 2023/6/6 15:49, Shuai Xue wrote: > > > >>>>>> This patchset adds the PCIe Performance Monitoring Unit (PMU) driver support > >>>>>> for T-Head Yitian 710 SoC chip. Yitian 710 is based on the Synopsys PCI Express > >>>>>> Core controller IP which provides statistics feature. > > > >> ... > >> Really a question for Bjorn I think, but here is my 2 cents... > >> > >> The problem here is that we need to do that fundamental redesign of the > >> way the PCI ports drivers work. I'm not sure there is a path to merging > >> this until that is done. The bigger problem is that I'm not sure anyone > >> is actively looking at that yet. I'd like to look at this (as I have > >> the same problem for some other drivers), but it is behind various > >> other things on my todo list. > >> > >> Bjorn might be persuaded on a temporary solution, but that would come > >> with some maintenance problems, particularly when we try to do it > >> 'right' in the future. Maybe adding another service driver would be > >> a stop gap as long as we know we won't keep doing so for ever. Not sure. > > > > I think the question here is around the for_each_pci_dev() in > > __dwc_pcie_pmu_probe()? I don't *like* that because of the > > assumptions it breaks (autoload doesn't work, hotplug doesn't work), > > but: > > > > - There are several other drivers that also do this, > > - I don't have a better suggest for any of them, > > - It's not a drivers/pci thing, so not really up to me anyway, > > > > so I don't have any problem with this being merged as-is, as long as > > you can live with the limitations. > > > > I don't think this series does anything to work around those > > limitations, i.e., it doesn't make up fake device IDs for module > > loading or fake events for hotplug, so it seems like we could improve > > the implementation later if we ever have a way to do it. > > > > Bjorn > > + Will > > Ok, thank you for confirmation, Bjorn. Then it comes to perf driver parts and > it is really a question for @Will I think. > > What's your opinion about merging this patch set, @Will? No fundamental objection from me, but I'll have a closer look when you post a version addressing the feedback from Jonathan and Yicong. Cheers, Will