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[2620:137:e000::1:20]) by mx.google.com with ESMTP id r12-20020a170903410c00b001b02e044c87si6792572pld.320.2023.07.31.02.02.00; Mon, 31 Jul 2023 02:02:13 -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; 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=fail (p=NONE sp=NONE dis=NONE) header.from=alibaba.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231663AbjGaHcD (ORCPT + 99 others); Mon, 31 Jul 2023 03:32:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40142 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231473AbjGaHbf (ORCPT ); Mon, 31 Jul 2023 03:31:35 -0400 Received: from out30-130.freemail.mail.aliyun.com (out30-130.freemail.mail.aliyun.com [115.124.30.130]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D474EDC; Mon, 31 Jul 2023 00:30:37 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R151e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045192;MF=xueshuai@linux.alibaba.com;NM=1;PH=DS;RN=14;SR=0;TI=SMTPD_---0VoaPEop_1690788632; Received: from 30.240.113.95(mailfrom:xueshuai@linux.alibaba.com fp:SMTPD_---0VoaPEop_1690788632) by smtp.aliyun-inc.com; Mon, 31 Jul 2023 15:30:34 +0800 Message-ID: <375a0706-b76e-e8a8-cdac-ed628af6643c@linux.alibaba.com> Date: Mon, 31 Jul 2023 15:30:31 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.13.1 Subject: Re: [PATCH v6 0/4] drivers/perf: add Synopsys DesignWare PCIe PMU driver support Content-Language: en-US To: Will Deacon 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 References: <20230725205955.GA665326@bhelgaas> <634f4762-cf2e-4535-f369-4032d65093f0@linux.alibaba.com> <20230728133926.GC21394@willie-the-truck> From: Shuai Xue In-Reply-To: <20230728133926.GC21394@willie-the-truck> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-10.0 required=5.0 tests=BAYES_00, ENV_AND_HDR_SPF_MATCH,NICE_REPLY_A,RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE, SPF_PASS,T_SCC_BODY_TEXT_LINE,UNPARSEABLE_RELAY,USER_IN_DEF_SPF_WL 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 2023/7/28 21:39, Will Deacon wrote: > 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. Thanks for your input! I appreciate that you don't have any fundamental objections to merging the patch set. I'll definitely take into account the feedback from Jonathan and Yicong before posting a revised version. Best Regards, Cheers. Shuai