From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756289Ab3BVELz (ORCPT ); Thu, 21 Feb 2013 23:11:55 -0500 Received: from na01-by1-obe.ptr.o365filtering.com ([64.4.22.92]:31017 "EHLO na01-by1-obe.outbound.o365filtering.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755487Ab3BVELs convert rfc822-to-8bit (ORCPT ); Thu, 21 Feb 2013 23:11:48 -0500 From: Haiyang Zhang To: Olaf Hering CC: "FlorianSchandinat@gmx.de" , "linux-fbdev@vger.kernel.org" , KY Srinivasan , "jasowang@redhat.com" , "linux-kernel@vger.kernel.org" , "devel@linuxdriverproject.org" Subject: RE: [PATCH RFC] video: Add Hyper-V Synthetic Video Frame Buffer Driver Thread-Topic: [PATCH RFC] video: Add Hyper-V Synthetic Video Frame Buffer Driver Thread-Index: AQHOC6xQKsSDc1Q1WkuxN29CXfjd55iB8XAA//+EDqCAAJpbgP//f3DggAN2zYCAAEMw0w== Date: Fri, 22 Feb 2013 04:11:39 +0000 Message-ID: References: <1360955396-14183-1-git-send-email-haiyangz@microsoft.com> <20130219165118.GA17715@aepfle.de> <1ca36b5d55c64ac6b8854c4f216ef8e5@DFM-TK5MBX15-06.exchange.corp.microsoft.com> <20130219184009.GA21783@aepfle.de> <7267f77544c24531b8fcccc2192b9f48@DFM-TK5MBX15-06.exchange.corp.microsoft.com>,<20130221155359.GA28637@aepfle.de> In-Reply-To: <20130221155359.GA28637@aepfle.de> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [157.54.51.13] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 X-Forefront-Antispam-Report: CIP:131.107.1.17;IPV:NLI;EFV:NLI;SFV:NSPM;SFS:(377454001)(51704002)(24454001)(164054002)(189002)(199002)(56776001)(76482001)(4396001)(31966008)(50986001)(44976002)(50466001)(23726001)(876001)(16406001)(51856001)(79102001)(5343655001)(59766001)(47446002)(77982001)(74662001)(74502001)(65816001)(54316002)(56816002)(47976001)(49866001)(47736001)(46406002)(47776003)(80022001)(33646001)(54356001)(46102001)(53806001)(20776003)(63696002)(66066001)(24736002);DIR:OUT;SFP:;SCL:1;SRVR:BLUSR01MB603;H:hybrid.exchange.microsoft.com;RD:mail1.exchange.microsoft.com;MX:1;A:1;LANG:en; X-Forefront-PRVS: 07658B8EA3 X-OriginatorOrg: DuplicateDomain-7923a859-03c9-4312-a77c-440aa45aaf52.microsoft.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > From: Olaf Hering > Sent: Thursday, February 21, 2013 10:53 AM > To: Haiyang Zhang > Cc: FlorianSchandinat@gmx.de; linux-fbdev@vger.kernel.org; KY Srinivasan; jasowang@redhat.com; linux-kernel@vger.kernel.org; devel@linuxdriverproject.org > Subject: Re: [PATCH RFC] video: Add Hyper-V Synthetic Video Frame Buffer Driver > > On Tue, Feb 19, Haiyang Zhang wrote: > > > In my test, the vesafb doesn't automatically give up the emulated video device, > > unless I add the DMI based mechanism to let it exit on Hyper-V. > > From reading the code, it seems to do that via > do_remove_conflicting_framebuffers(). hypervfb does not set apertures > etc, so that function is a noop. We are currently allocating a new framebuffer for hyperv_fb, which is different from the framebuffer for the emulated video. So this cannot be detected by do_remove_conflicting_framebuffers() based on apertures_overlap(). > My point is that with this new driver distro kernel will have no console > output until hypervfb is loaded. On native hardware there is at least > vesafb which can display something until initrd is running. So if the > hypervisor allows that hypervfb can shutdown the emulated vesa hardware > then it should do that. Since the generic vga driver starts to work early in the boot process, the console messages are still displayed without vesafb. Actually, I didn't see any console messages missing when comparing it to the original VM before my patch. Thanks, - Haiyang