From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753067AbbCHRLt (ORCPT ); Sun, 8 Mar 2015 13:11:49 -0400 Received: from cantor2.suse.de ([195.135.220.15]:56617 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752829AbbCHRLq (ORCPT ); Sun, 8 Mar 2015 13:11:46 -0400 Date: Sun, 8 Mar 2015 18:11:40 +0100 From: Jean Delvare To: Ard Biesheuvel Cc: "Ivan.khoronzhuk" , dmidecode-devel@nongnu.org, Ivan Khoronzhuk , Matt Fleming , "linux-kernel@vger.kernel.org" , Leif Lindholm , Mark Salter , Grant Likely Subject: Re: [dmidecode] [Patch v3] firmware: dmi-sysfs: add SMBIOS entry point area raw attribute Message-ID: <20150308181140.288dfa88@endymion.delvare> In-Reply-To: References: <1422448763-17583-1-git-send-email-ivan.khoronzhuk@linaro.org> <1422975508.18187.77.camel@deneb.redhat.com> <54D0EDE8.40207@linaro.org> <1424940642.25006.60.camel@chaos.site> <20150226104134.178e8c35@endymion.delvare> <54F6FA64.7000609@globallogic.com> <20150305084656.36d639a6@endymion.delvare> <54FB654C.2030601@globallogic.com> <20150308123125.7b324e47@endymion.delvare> Organization: SUSE Linux X-Mailer: Claws Mail 3.10.1 (GTK+ 2.24.23; x86_64-suse-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 8 Mar 2015 14:53:04 +0100, Ard Biesheuvel wrote: > On 8 March 2015 at 12:31, Jean Delvare wrote: > > On Sat, 07 Mar 2015 22:53:32 +0200, Ivan.khoronzhuk wrote: > >> The specification doesn't oblige firmware to provide two entry points. > >> An implementation may provide either the 32-bit entry point or the 64-bit > >> entry point, or both. For compatibility with existing SMBIOS parsers, an > >> implementation should provide the 32-bit entry point, but it's not required. > > > > I expect most implementations will do, as it's trivial to implement. > > Not quite. First of all, some 64-bit ARM systems do not have any > system RAM below 4 GB, so there is not way they can implement the > 32-bit entry point. I didn't know that, thanks for the notice. No big deal anyway, these systems did not support SMBIOS before version 3.0 so there cannot be any regression on these systems. > Also, the 64-bit entry point does not limit the > structure size or the entire table to 64 KB like the 32-bit one does, > so it may be necessary to create a whole separate table with a subset > of the contents of the real table to stay within limits for the 32-bit > entry point. I doubt this is an issue in practice. I have been around for quite some time now and the largest table I've ever seen was 9043 byte long, which is nowhere close to the limit. > And the 32-bit entry point could well be 3.0 anyway, if > it uses any of the new enum values for the data items that were > undefined before 3.0. This is true but irrelevant to the discussion. Thanks, -- Jean Delvare SUSE L3 Support