From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx4+mQTm+OeWzj8uXNx/ms6/NdWZM0hgGfcycgO3PahqPMboEjjxiZfTgPuKJ/i8p/8zvrAVf ARC-Seal: i=1; a=rsa-sha256; t=1523889007; cv=none; d=google.com; s=arc-20160816; b=K492Qg3OQv8Bl0EaKtRkA+dDazGFfLBfhxWXV2ysL+W/UMqsCk8SrjfVEPvT/K2j9J URsFtN9CzIXzSyO4uf4KCImaHDlk3ALw+2vR40F7KkVjui5js3DcLP6Aoxrcavv5PNRf 1GCJS76oTiXabPAen4FAKPYkdh+keZs2SpAhGcoh6uWTlwtWOE2ds1+PcSE4+PEfYOiC W3UHZrSbeNuk3ZFbCv6t/uI/BIx0BWBkvuYUq/h2bIqrNjgomxDYA+1KhPte2oqdTVXl qRgpl5Ec41AszE0un8Y8cPYSkt+GxhxBBe51GKnCPRG1+3bjIdp0nNnbvWlCvUVCr9BT YIjg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:content-language:in-reply-to:mime-version :user-agent:date:message-id:from:references:cc:to:subject :dmarc-filter:dkim-signature:dkim-signature :arc-authentication-results; bh=dxDP2BzgPHof10QGtW/RcbSQZgsmbGO1bb08sW1rhtI=; b=TWSCQFzb5hT6YYN2XYj5lPeWIZOQgE2cqtEYseSF09jWTcgrpQNOdfTdIBjxaQ32JN PDw9iG0x0dbhBa9En+ubY0KfoLy6o+/BD5q9R1VexCCU+XbBkScJHyy27X9bulHAZgig ftkISbH762Gqy8pEDy897uDCbaUt78xc/mVPlPikbSNazzALVBXqks4U8+CdicNqM/dV DjG/hU0I5O06Ygz0+ozT6uLL5DgsSKkpxE4YzTuIYQny+ylSrNR1bFPuquirnnAqGdfp lJt+SNFjKp14fFJMeYNXm/A/wE/b6ZIYGPvbNIJwOiF67o9Z9gVhDWI7Su4/QW+iYWUs YKbA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@codeaurora.org header.s=default header.b=dFllkS3Q; dkim=pass header.i=@codeaurora.org header.s=default header.b=WEZTJSBD; spf=pass (google.com: domain of okaya@codeaurora.org designates 198.145.29.96 as permitted sender) smtp.mailfrom=okaya@codeaurora.org Authentication-Results: mx.google.com; dkim=pass header.i=@codeaurora.org header.s=default header.b=dFllkS3Q; dkim=pass header.i=@codeaurora.org header.s=default header.b=WEZTJSBD; spf=pass (google.com: domain of okaya@codeaurora.org designates 198.145.29.96 as permitted sender) smtp.mailfrom=okaya@codeaurora.org DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org A017B601E6 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=okaya@codeaurora.org Subject: Re: [PATCH v13 0/6] Address error and recovery for AER and DPC To: Bjorn Helgaas , poza@codeaurora.org Cc: Bjorn Helgaas , Philippe Ombredanne , Thomas Gleixner , Greg Kroah-Hartman , Kate Stewart , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Dongdong Liu , Keith Busch , Wei Zhang , Timur Tabi References: <1523284914-2037-1-git-send-email-poza@codeaurora.org> <20180416031600.GB80087@bhelgaas-glaptop.roam.corp.google.com> <5b4e667f-bead-a007-78dd-e42d3194f232@codeaurora.org> <9301606a70a213c180d9e6764b002cf9@codeaurora.org> <20180416132753.GA28657@bhelgaas-glaptop.roam.corp.google.com> From: Sinan Kaya Message-ID: <91420f0f-31c1-0d82-63cc-627fb4920b6d@codeaurora.org> Date: Mon, 16 Apr 2018 10:30:03 -0400 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <20180416132753.GA28657@bhelgaas-glaptop.roam.corp.google.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1597280027023020186?= X-GMAIL-MSGID: =?utf-8?q?1597913439570698062?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On 4/16/2018 9:27 AM, Bjorn Helgaas wrote: >>> We realized that DPC and hotplug is heavily integrated today. We >>> have use cases for systems without hotplug support but still >>> support DPC. That's the problem we are trying to solve with this >>> patchset. > Apparently there's a problem with systems that have DPC but not > hotplug. It will be extremely helpful if you can articulate what that > problem is and include it in the appropriate changelog. > At a higher level, the DPC driver performs the stop operation regardless of hotplug. However, DPC driver relies on hotplug driver observing link up to re-enumerate. Of course, when the system didn't support hotplug; there was nobody to restore functionality. Our initial attempt was to also do a re-enumeration in the DPC driver regardless of hotplug driver in the system or not. If hotplug driver is present, it would observe two enumerations. It still worked as long as these were protected by a mutex. Then, we got your input that you want DPC and AER to behave the same. We started converging towards the AER path. -- Sinan Kaya Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.