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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_NEOMUTT 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 C38B2ECE563 for ; Mon, 17 Sep 2018 08:50:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 78878214AB for ; Mon, 17 Sep 2018 08:50:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 78878214AB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728121AbeIQORD (ORCPT ); Mon, 17 Sep 2018 10:17:03 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38282 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727133AbeIQORD (ORCPT ); Mon, 17 Sep 2018 10:17:03 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 44BB180F7A; Mon, 17 Sep 2018 08:50:37 +0000 (UTC) Received: from sirius.home.kraxel.org (ovpn-116-56.phx2.redhat.com [10.3.116.56]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8251A4C494; Mon, 17 Sep 2018 08:50:34 +0000 (UTC) Received: by sirius.home.kraxel.org (Postfix, from userid 1000) id 56CB54F973; Mon, 17 Sep 2018 10:50:33 +0200 (CEST) Date: Mon, 17 Sep 2018 10:50:33 +0200 From: Gerd Hoffmann To: Zhenyu Wang Cc: Alex Williamson , Kirti Wankhede , intel-gvt-dev@lists.freedesktop.org, open list , kvm@vger.kernel.org Subject: Re: [PATCH 1/2] vfio: add edid api for display (vgpu) devices. Message-ID: <20180917085033.ttcs3cpznnf3wngd@sirius.home.kraxel.org> References: <20180913054745.6353-1-kraxel@redhat.com> <20180913054745.6353-2-kraxel@redhat.com> <20180913115139.02775316@t450s.home> <20180914122552.3xmepqo7azzmx7ky@sirius.home.kraxel.org> <20180917065154.GI20737@zhen-hp.sh.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180917065154.GI20737@zhen-hp.sh.intel.com> User-Agent: NeoMutt/20180716 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Mon, 17 Sep 2018 08:50:37 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > +#define VFIO_DEVICE_INFO_CAP_EDID 1 > > + > > +struct vfio_device_info_edid_cap { > > + struct vfio_info_cap_header header; > > + __u32 max_x; /* Max display height (zero == no limit) */ > > + __u32 max_y; /* Max display height (zero == no limit) */ > > +}; > > As current virtual display for Intel vGPU is still emulating against real HW > pipeline with same limitations, asked display developers that whether or not > specific mode can work might still depend on current or future HW behavior. > So could we add some hints on what kind of edid mode vfio device can operate? > Some may support arbitrary modes, but some may only support standard modes. What kind of restrictions do we have here? Really to a fixed list of standard modes? Some testing (kaby lake) indicates y axis has no restrictions and x axis gets rounded up to the next multiple of 8 pixels (32 bytes), maybe to align scanlines with cachelines? Oh, and btw: Seems the resolution restriction (to 1024x768 for the smallest vgpu type) seems to not be enforced. Intentional? cheers, Gerd