From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 07C87C433DF for ; Tue, 30 Jun 2020 07:04:34 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D3C71206CB for ; Tue, 30 Jun 2020 07:04:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D3C71206CB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jqAJI-00049M-CR; Tue, 30 Jun 2020 07:04:04 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jqAJH-00049H-O1 for xen-devel@lists.xenproject.org; Tue, 30 Jun 2020 07:04:03 +0000 X-Inumbo-ID: e0897bba-ba9f-11ea-8496-bc764e2007e4 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id e0897bba-ba9f-11ea-8496-bc764e2007e4; Tue, 30 Jun 2020 07:04:02 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 6C4F3AAC3; Tue, 30 Jun 2020 07:04:01 +0000 (UTC) Subject: Re: [PATCH 1/2] xen/displif: Protocol version 2 To: Oleksandr Andrushchenko , Oleksandr Andrushchenko , "xen-devel@lists.xenproject.org" , "ian.jackson@eu.citrix.com" , "wei.liu2@citrix.com" , "konrad.wilk@oracle.com" References: <20200520090425.28558-1-andr2000@gmail.com> <20200520090425.28558-2-andr2000@gmail.com> <84d975e3-0cea-becb-f505-856368a63fb7@suse.com> From: =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= Message-ID: Date: Tue, 30 Jun 2020 09:03:59 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" On 30.06.20 08:13, Oleksandr Andrushchenko wrote: > On 6/29/20 10:02 AM, Jürgen Groß wrote: >> On 20.05.20 11:04, Oleksandr Andrushchenko wrote: >>> From: Oleksandr Andrushchenko >>> >>> 1. Change protocol version from string to integer >>> >>> Version string, which is in fact an integer, is hard to handle in the >>> code that supports different protocol versions. To simplify that >>> make the version an integer. >>> >>> 2. Pass buffer offset with XENDISPL_OP_DBUF_CREATE >>> >>> There are cases when display data buffer is created with non-zero >>> offset to the data start. Handle such cases and provide that offset >>> while creating a display buffer. >>> >>> 3. Add XENDISPL_OP_GET_EDID command >>> >>> Add an optional request for reading Extended Display Identification >>> Data (EDID) structure which allows better configuration of the >>> display connectors over the configuration set in XenStore. >>> With this change connectors may have multiple resolutions defined >>> with respect to detailed timing definitions and additional properties >>> normally provided by displays. >>> >>> If this request is not supported by the backend then visible area >>> is defined by the relevant XenStore's "resolution" property. >>> >>> If backend provides extended display identification data (EDID) with >>> XENDISPL_OP_GET_EDID request then EDID values must take precedence >>> over the resolutions defined in XenStore. >>> >>> 4. Bump protocol version to 2. >>> >>> Signed-off-by: Oleksandr Andrushchenko >>> --- >>>   xen/include/public/io/displif.h | 83 +++++++++++++++++++++++++++++++-- >>>   1 file changed, 80 insertions(+), 3 deletions(-) >>> >>> diff --git a/xen/include/public/io/displif.h b/xen/include/public/io/displif.h >>> index cc5de9cb1f35..4d43ba5078c8 100644 >>> --- a/xen/include/public/io/displif.h >>> +++ b/xen/include/public/io/displif.h >>> @@ -38,7 +38,7 @@ >>>    *                           Protocol version >>> ****************************************************************************** >>>    */ >>> -#define XENDISPL_PROTOCOL_VERSION     "1" >>> +#define XENDISPL_PROTOCOL_VERSION     2 >> >> This is not very nice regarding compatibility. >> >> Can't you add a new macro for the integer value? > > We can leave it as is, e.g. define XENDISPL_PROTOCOL_VERSION as "2", > > so we do not break the existing users. Then if every user of the header has > > its local copy (this is what we now use in the display backend), then that > local copy can be changed in a way suitable for the concrete user, e.g. "2" > > redefined to 2. This cannot be done (?) for the Linux Kernel though. > > Or we can have > > #define XENDISPL_PROTOCOL_VERSION     "2" > > #define XENDISPL_PROTOCOL_VERSION_INT  2 > > Jurgen, what's your preference here? I would prefer the latter, as it avoids the need to modify the header when copying it to a local project. Juergen