Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753177Ab3FZVbE (ORCPT ); Wed, 26 Jun 2013 17:31:04 -0400 Received: from terminus.zytor.com ([198.137.202.10]:40568 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753005Ab3FZVbB (ORCPT ); Wed, 26 Jun 2013 17:31:01 -0400 Message-ID: <51CB5D84.4080709@zytor.com> Date: Wed, 26 Jun 2013 14:30:44 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130514 Thunderbird/17.0.6 MIME-Version: 1.0 To: Bjorn Helgaas CC: Darren Hart , Linux Kernel Mailing List , Peter P Waskiewicz Jr , Andy Shevchenko , danders@circuitco.com, vishal.l.verma@intel.com, "linux-pci@vger.kernel.org" Subject: Re: [PATCH 7/8] pci: Add CircuitCo VENDOR ID and MinnowBoard DEVICE ID References: <83879b07cd4ce95f086420d1faa926c1692d63b4.1372211451.git.dvhart@linux.intel.com> <20130626163250.GA29299@google.com> <1372266904.8177.83.camel@envy.home> In-Reply-To: X-Enigmail-Version: 1.5.1 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1460 Lines: 35 On 06/26/2013 12:37 PM, Bjorn Helgaas wrote: > > Yeah, that's what I was thinking. > > But Peter's comment makes more sense to me now. The spec refers to > that config register as "Subsystem ID," not "Subsystem Device ID," but > I was confused because most existing usage treats it as a device ID. > For example, the field in struct pci_device_id is named "subdevice," > and all the existing #defines in pci_ids.h are of the form > PCI_SUBDEVICE_ID_*. > > Device IDs are pretty specific identifiers, so I was thinking that a > "sub-device ID" would be even more specific. Then it would make no > sense to have a "sub-device ID" that was as generic as "MINNOWBOARD." > But the register is actually *not* a "sub-device ID," and I can see > that using the same Subsystem ID for all the devices on a board might > make sense. > Subsystem IDs is basically a board ID in the traditional PC view, but they didn't call it that because it would have been confusing in other, nontraditional configurations. Microsoft has a "best practices" document, which may end up becoming basis for a future PCI-SIG document clarifying the standard: http://msdn.microsoft.com/en-us/library/windows/hardware/gg463287.aspx -hpa -- 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/