From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755317Ab3BUPyF (ORCPT ); Thu, 21 Feb 2013 10:54:05 -0500 Received: from mo-p00-ob.rzone.de ([81.169.146.160]:34565 "EHLO mo-p00-ob.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755228Ab3BUPyD (ORCPT ); Thu, 21 Feb 2013 10:54:03 -0500 X-RZG-AUTH: :P2EQZWCpfu+qG7CngxMFH1J+yackYocTD1iAi8x+OWJ8KkvZ5r/UwZ5vFU8= X-RZG-CLASS-ID: mo00 Date: Thu, 21 Feb 2013 16:53:59 +0100 From: Olaf Hering 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 Message-ID: <20130221155359.GA28637@aepfle.de> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <7267f77544c24531b8fcccc2192b9f48@DFM-TK5MBX15-06.exchange.corp.microsoft.com> User-Agent: Mutt/1.5.21.rev5638 (2013-02-08) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 19, Haiyang Zhang wrote: > > I havent read the vesafb code, but I think it can kind of give up the > > hardware, something ata_piix can not do. > > 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. 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. Olaf From mboxrd@z Thu Jan 1 00:00:00 1970 From: Olaf Hering Date: Thu, 21 Feb 2013 15:53:59 +0000 Subject: Re: [PATCH RFC] video: Add Hyper-V Synthetic Video Frame Buffer Driver Message-Id: <20130221155359.GA28637@aepfle.de> List-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> In-Reply-To: <7267f77544c24531b8fcccc2192b9f48@DFM-TK5MBX15-06.exchange.corp.microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit 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" On Tue, Feb 19, Haiyang Zhang wrote: > > I havent read the vesafb code, but I think it can kind of give up the > > hardware, something ata_piix can not do. > > 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. 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. Olaf