From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.71) id 1cEOcS-0006C4-7F for mharc-grub-devel@gnu.org; Tue, 06 Dec 2016 17:53:52 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52487) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cEOcQ-0006AO-FR for grub-devel@gnu.org; Tue, 06 Dec 2016 17:53:51 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cEOcN-0005nJ-Di for grub-devel@gnu.org; Tue, 06 Dec 2016 17:53:50 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:33105) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cEOcN-0005n9-3t for grub-devel@gnu.org; Tue, 06 Dec 2016 17:53:47 -0500 Received: from userv0021.oracle.com (userv0021.oracle.com [156.151.31.71]) by aserp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id uB6Mrhbs003132 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 6 Dec 2016 22:53:43 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userv0021.oracle.com (8.14.4/8.14.4) with ESMTP id uB6Mrh3d009726 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 6 Dec 2016 22:53:43 GMT Received: from abhmp0009.oracle.com (abhmp0009.oracle.com [141.146.116.15]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id uB6Mrg7d026039; Tue, 6 Dec 2016 22:53:42 GMT Received: from olila.local.net-space.pl (/10.175.227.19) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 06 Dec 2016 14:53:41 -0800 From: Daniel Kiper To: grub-devel@gnu.org, xen-devel@lists.xenproject.org Cc: andrew.cooper3@citrix.com, arvidjaar@gmail.com, eric.snowberg@oracle.com, jgross@suse.com, konrad.wilk@oracle.com, phcoder@gmail.com, seth.goldberg@oracle.com, tsoome@me.com Subject: [MULTIBOOT2 DOC PATCH v3 05/13] multiboot2: Clarify meaning of information request header tag Date: Tue, 6 Dec 2016 23:52:53 +0100 Message-Id: <1481064781-16949-6-git-send-email-daniel.kiper@oracle.com> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1481064781-16949-1-git-send-email-daniel.kiper@oracle.com> References: <1481064781-16949-1-git-send-email-daniel.kiper@oracle.com> X-Source-IP: userv0021.oracle.com [156.151.31.71] X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.4.x-2.6.x [generic] [fuzzy] X-Received-From: 141.146.126.69 X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: The development of GNU GRUB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 06 Dec 2016 22:53:51 -0000 Signed-off-by: Daniel Kiper --- v2 - suggestions/fixes: - rephrase some sentences (suggested by Andrew Cooper), - add missing the articles (suggested by Andrew Cooper). --- doc/multiboot.texi | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/doc/multiboot.texi b/doc/multiboot.texi index a9cba9b..4f838f0 100644 --- a/doc/multiboot.texi +++ b/doc/multiboot.texi @@ -437,15 +437,19 @@ u32[n] | mbi_tag_types | @end group @end example -@samp{mbi_tag_types} is an array of u32 each one representing an information -request -If this tag is present and @samp{optional} is set to @samp{0} information -conveyed by requested tag types must be present. If bootloader is unable -to supply this information it must fail with an error +@samp{mbi_tag_types} is an array of u32's, each one representing an information request. -Note: it doesn't garantee that any tags of type @samp{mbi_tag_types} will -actually be present. E.g. on a videoless system even if you requested tag -@samp{8} no tags of type @samp{8} will be present in mbi. +If this tag is present and @samp{optional} is set to @samp{0}, the bootloader must +support the requested tag and be able to provide relevant information to the image +if it is available. If the bootloader does not understand the meaning of the requested +tag it must fail with an error. However, if it supports a given tag but the information +conveyed by it is not available the bootloader does not provide the requested tag in +the Multiboot2 information structure and passes control to the loaded image as usual. + +Note: The above means that there is no guarantee that any tags of type @samp{mbi_tag_types} +will actually be present. E.g. on a videoless system even if you requested tag @samp{8} +and the bootloader supports it, no tags of type @samp{8} will be present in the Multiboot2 +information structure. @node Address header tag -- 1.7.10.4