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_HELO_NONE,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 47ABDC48BD7 for ; Thu, 27 Jun 2019 06:22:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2505120663 for ; Thu, 27 Jun 2019 06:22:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726635AbfF0GWf (ORCPT ); Thu, 27 Jun 2019 02:22:35 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53494 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725385AbfF0GWf (ORCPT ); Thu, 27 Jun 2019 02:22:35 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 6CEF1356CD; Thu, 27 Jun 2019 06:22:35 +0000 (UTC) Received: from sirius.home.kraxel.org (ovpn-116-96.ams2.redhat.com [10.36.116.96]) by smtp.corp.redhat.com (Postfix) with ESMTP id CC06B5D719; Thu, 27 Jun 2019 06:22:32 +0000 (UTC) Received: by sirius.home.kraxel.org (Postfix, from userid 1000) id EB94016E08; Thu, 27 Jun 2019 08:22:31 +0200 (CEST) Date: Thu, 27 Jun 2019 08:22:31 +0200 From: Gerd Hoffmann To: Tina Zhang Cc: intel-gvt-dev@lists.freedesktop.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, zhenyuw@linux.intel.com, zhiyuan.lv@intel.com, zhi.a.wang@intel.com, kevin.tian@intel.com, hang.yuan@intel.com, alex.williamson@redhat.com Subject: Re: [RFC PATCH v3 0/4] Deliver vGPU display vblank event to userspace Message-ID: <20190627062231.57tywityo6uyhmyd@sirius.home.kraxel.org> References: <20190627033802.1663-1-tina.zhang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190627033802.1663-1-tina.zhang@intel.com> User-Agent: NeoMutt/20180716 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Thu, 27 Jun 2019 06:22:35 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, > Instead of delivering page flip events, we choose to post display vblank > event. Handling page flip events for both primary plane and cursor plane > may make user space quite busy, although we have the mask/unmask mechansim > for mitigation. Besides, there are some cases that guest app only uses > one framebuffer for both drawing and display. In such case, guest OS won't > do the plane page flip when the framebuffer is updated, thus the user > land won't be notified about the updated framebuffer. What happens when the guest is idle and doesn't draw anything to the framebuffer? cheers, Gerd