Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762245Ab2FHRbo (ORCPT ); Fri, 8 Jun 2012 13:31:44 -0400 Received: from mail-lb0-f174.google.com ([209.85.217.174]:37574 "EHLO mail-lb0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753774Ab2FHRbl (ORCPT ); Fri, 8 Jun 2012 13:31:41 -0400 MIME-Version: 1.0 In-Reply-To: <1339142492-13625-1-git-send-email-xudong.hao@intel.com> References: <1339142492-13625-1-git-send-email-xudong.hao@intel.com> From: Bjorn Helgaas Date: Fri, 8 Jun 2012 10:31:19 -0700 Message-ID: Subject: Re: [PATCH 0/4] PCI: Enable LTR/OBFF before device is used by driver To: Xudong Hao Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, avi@redhat.com, alex.williamson@redhat.com, ddutile@redhat.com, myron.stowe@redhat.com, xiantao.zhang@intel.com Content-Type: text/plain; charset=ISO-8859-1 X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1232 Lines: 27 On Fri, Jun 8, 2012 at 1:01 AM, Xudong Hao wrote: > The series of patches enable LTR and OBFF before device is used by driver, and > introduce a couple of functions to save/restore LTR latency value. > > Patch 1/4 introduce new function pci_obff_supported() as pci_ltr_support(). > > Patch 2/4 enable LTR(Latency tolerance reporting) before device is used by > driver. > > Patch 3/4 enable OBFF(optimized buffer flush/fill) before device is used by > driver. > > Patch 4/4 introduce a couple of functions pci_save_ltr_value() and > pci_restore_ltr_value() to save and restore LTR latency value, while device is > reset. We need some justification for these patches. Why do we want them? Do they improve performance? Reduce power consumption? How have they been tested? How can we be confident that these features work correctly on hardware in the field? Should or could the BIOS enable them itself, based on OEM testing and desire to support these features? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/