From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760487AbaJCXjh (ORCPT ); Fri, 3 Oct 2014 19:39:37 -0400 Received: from v094114.home.net.pl ([79.96.170.134]:60383 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1760470AbaJCXib (ORCPT ); Fri, 3 Oct 2014 19:38:31 -0400 From: "Rafael J. Wysocki" To: Arnd Bergmann Cc: Mark Rutland , Mika Westerberg , "linux-kernel@vger.kernel.org" , "linux-acpi@vger.kernel.org" , "devicetree@vger.kernel.org" , Greg Kroah-Hartman , Linus Walleij , Alexandre Courbot , Dmitry Torokhov , Bryan Wu , Lee Jones , "grant.likely@linaro.org" , Aaron Lu , Darren Hart Subject: Re: [PATCH v3 04/15] ACPI: Document ACPI device specific properties Date: Sat, 04 Oct 2014 01:58:30 +0200 Message-ID: <1817639.W8PYrU1iOP@vostro.rjw.lan> User-Agent: KMail/4.11.5 (Linux/3.16.0-rc5+; KDE/4.11.5; x86_64; ; ) In-Reply-To: <2784760.Rf0vOml5OQ@wuerfel> References: <1410868367-11056-1-git-send-email-mika.westerberg@linux.intel.com> <20141003135610.GM26643@leverpostej> <2784760.Rf0vOml5OQ@wuerfel> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday, October 03, 2014 05:02:13 PM Arnd Bergmann wrote: > On Friday 03 October 2014 14:56:10 Mark Rutland wrote: > > On Thu, Oct 02, 2014 at 03:55:56PM +0100, Arnd Bergmann wrote: > > > On Thursday 02 October 2014 17:38:09 Mika Westerberg wrote: > > > > On Thu, Oct 02, 2014 at 04:29:03PM +0200, Arnd Bergmann wrote: > > > > > Is this a limitation in the way that the AML syntax and compiler works, > > > > > or is this a decision you made specifically for the _DSD syntax and that > > > > > could still be changed if there is an overwhelming interest? > > > > > > > > It is only limitation of the _DSD device property UUID specification and > > > > our implementation. It can be changed if needed. > > > > > > Ok, I see. I think it would be nice if this could be changed in order > > > to avoid having to copy the #xxx-cells and xxx-names properties from > > > DT, by providing a more natural syntax. > > > > I'd certainly not like to see #foo-cells in _DSD given it should be > > possible with a package to have a package description like the > > following: > > > > Package () { > > Package () { ^ref1, data, data }, > > Package () { ^ref2, dta, data, data }, > > } > > > > Where the #foo-cells is implicit in each instance. That makes variadic > > properties possible, and makes it possible to perform validation on each > > tuple even in the binary format, which we can't do with a DTB > > > > I'm not so sure on foo-names unless we made names an explicit > > requirement from the start (which I wish was the case on the DT side). > > Even then we might need other parallel properties anyway (think > > clock-indicies). > > I suppose it might even be possible to define the ACPI references to > have an optional string, so you can do > > Package () { > Package () { ^ref1, data, data }, > Package () { "foo", ^ref2, data, data, data }, > } > > The parser should be able to interpret both anonymous and named > references just by looking at the type of the first member. > You might not want to allow mixing them in a single property, but > that is more a style question than a technical requirement. Yes, that only is a matter of implementing the parser. For now, it simply is easier for us to parse the Package () { ^ref1, data, data } format only, because we have functions for parsing lists of strings, lists of numbers etc. for other purposes anyway and we can re-use them for the names etc. I don't see a reason why the parser cannot be extended in the future to handle "all in one" packages, but not necessarily at the moment. -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.