From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mika Westerberg Subject: Re: [PATCH 2/3] spi / ACPI: add ACPI enumeration support Date: Mon, 5 Nov 2012 20:08:47 +0200 Message-ID: <20121105180847.GK24532@intel.com> References: <1351928793-14375-1-git-send-email-mika.westerberg@linux.intel.com> <20121105150326.3bbf69df@endymion.delvare> <1925265.4Cx64DgKbB@vostro.rjw.lan> <20121105145315.GI24532@intel.com> <20121105161920.44e8e1cb@endymion.delvare> <20121105171248.GJ24532@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mga09.intel.com ([134.134.136.24]:57949 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754264Ab2KESGi (ORCPT ); Mon, 5 Nov 2012 13:06:38 -0500 Content-Disposition: inline In-Reply-To: Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Bjorn Helgaas Cc: Jean Delvare , "Rafael J. Wysocki" , Linus Walleij , Mark Brown , linux-kernel@vger.kernel.org, lenb@kernel.org, rafael.j.wysocki@intel.com, grant.likely@secretlab.ca, ben-linux@fluff.org, w.sang@pengutronix.de, mathias.nyman@linux.intel.com, linux-acpi@vger.kernel.org On Mon, Nov 05, 2012 at 10:43:17AM -0700, Bjorn Helgaas wrote: > > It should already be unique in case of ACPI. We use ACPI _HID and _UID to > > achieve that. > > Using only _HID and _UID to guarantee uniqueness means you're relying > on a property of the BIOS, so you're vulnerable to BIOS bugs. > > If there's an ACPI Device for I2C adapters, why wouldn't you just use > its device name as set in acpi_device_register() (basically a _HID + > instance number)? That's a good point - we could change to use that instead (the platform code in linux-pm tree uses _HID + _UID but I guess it is pretty trivial to change).