From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933735AbeB1Te2 (ORCPT ); Wed, 28 Feb 2018 14:34:28 -0500 Received: from mga03.intel.com ([134.134.136.65]:45525 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932389AbeB1Te0 (ORCPT ); Wed, 28 Feb 2018 14:34:26 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.47,406,1515484800"; d="scan'208";a="21041991" Message-ID: <1519846461.10722.309.camel@linux.intel.com> Subject: Re: [PATCH v1 2/4] x86/pci: Re-use new dmi_get_bios_year() helper From: Andy Shevchenko To: Jean Delvare , "Rafael J. Wysocki" Cc: Bjorn Helgaas , Linux PCI , "Rafael J. Wysocki" , ACPI Devel Maling List , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , the arch/x86 maintainers , Linux Kernel Mailing List Date: Wed, 28 Feb 2018 21:34:21 +0200 In-Reply-To: <20180228202144.2ae8149f@endymion> References: <20180222125923.57385-1-andriy.shevchenko@linux.intel.com> <20180222125923.57385-2-andriy.shevchenko@linux.intel.com> <20180226172832.7bf82336@endymion> <1519813744.10722.258.camel@linux.intel.com> <20180228202144.2ae8149f@endymion> Organization: Intel Finland Oy Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.26.5-1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2018-02-28 at 20:21 +0100, Jean Delvare wrote: > On Wed, 28 Feb 2018 11:33:39 +0100, Rafael J. Wysocki wrote: > > On Wed, Feb 28, 2018 at 11:29 AM, Andy Shevchenko > > wrote: > > > I would assume that no BIOS date is related to prehistoric > > > firmwares and > > > using _CRS would sound weird on them. > > > > Careful here. > > > > You seem to be assuming that the DMI information is always valid > > and/or complete which is know to not be the case sometimes. > > True. While the BIOS date is not the worst offender when it comes to > broken DMI data, you must remember that the date comes as a string, > and > older SMBIOS specifications did not even recommend a specific format > for that string. As a matter of fact, my collection of DMI tables > includes a few creative samples like "Jul 7 2016" or "09-16-08" which > the kernel fails to parse. > > So the default behavior at the driver level shouldn't be based on what > older systems are most likely to enjoy. The default behavior must be > the safest option, regardless of the age of the system. Yep. And here is a very good question which path is more safer: use _CRS, or not? Rafael, do you know any consequences of not using _CRS for PCI on older and newer machines? -- Andy Shevchenko Intel Finland Oy