From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pz0-f46.google.com ([209.85.210.46]:37655 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966338Ab2EQPnO (ORCPT ); Thu, 17 May 2012 11:43:14 -0400 Received: by dady13 with SMTP id y13so2572548dad.19 for ; Thu, 17 May 2012 08:43:14 -0700 (PDT) Message-ID: <4FB51C89.5080905@gmail.com> Date: Thu, 17 May 2012 23:43:05 +0800 From: Jiang Liu MIME-Version: 1.0 To: Dan Williams CC: Vinod Koul , "linux-pci@vger.kernel.org" , Jiang Liu Subject: Re: [PATCH v1 0/8] enhance dmaengine core to support DMA device hotplug Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-pci-owner@vger.kernel.org List-ID: >On Mon, Apr 23, 2012 at 6:51 AM, Jiang Liu wrote: >> From: Jiang Liu >> >> This patchset tries to enhance the dmaengine and its clients to support >> hot-removal of DMA devices at runtime, especially for IOAT devices. >> >> When hot-removing IOH (PCI host bridge) on Intel Nehalem/Westmere platform, >> we need to remove all IOAT devices embedded in the IOH. For future Intel >> processor with IIO (Embedded IOH), we need to remove IOAT devices even >> when hot-removing a physical processor. But current dmaengine implementation >> doesn't support hot-removal of IOAT devices at runtime. > >Removal of the host bridge means several devices disappear at once. >Is it safe to assume that this action is coordinated by userspace? >I.e. is the kernel given a chance to shut everything down and remove >drivers, or is this a "surprise" unplug? Hi Dan, Sorry for late reply! I just noticed this mail by browsing the linux-pci mail list web archive just now. Yes, it will be coordinated by user/kernel hotplug manager. We don't plan to support surprisingly removal yet. It seems a little craze to support that. Thanks! Gerry