From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: Graphics pass-through Date: Mon, 09 May 2011 13:14:59 +0200 Message-ID: <4DC7CCB3.8030607@siemens.com> References: <4D415D70.8070105@web.de> <1296175554.2891.29.camel@x201> <4DC264CD.9080700@siemens.com> <1304608642.3081.35.camel@x201> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: =?UTF-8?B?QW5kcsOpIFdlaWRlbWFubg==?= , Prasad Joshi , "kvm@vger.kernel.org" , Oswaldo Cadenas To: Alex Williamson Return-path: Received: from goliath.siemens.de ([192.35.17.28]:30847 "EHLO goliath.siemens.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752220Ab1EILPG (ORCPT ); Mon, 9 May 2011 07:15:06 -0400 In-Reply-To: <1304608642.3081.35.camel@x201> Sender: kvm-owner@vger.kernel.org List-ID: On 2011-05-05 17:17, Alex Williamson wrote: >> And what about the host? When does Linux release the legacy range? >> Always or only when a specific (!=vga/vesa) framebuffer driver is loaded? > > Well, that's where it'd be nice if the vga arbiter was actually in more > widespread use. It currently seems to be nothing more than a shared > mutex, but it would actually be useful if it included backends to do the > chipset vga routing changes. I think when I was testing this, I was > externally poking PCI bridge chipset to toggle the VGA_EN bit. Right, we had to drop the approach to pass through the secondary card for now, the arbiter was not switching properly. Haven't checked yet if VGA_EN was properly set, though the kernel code looks like it should take care of this. Even with handing out the primary adapter, we had only mixed success so far. The onboard adapter worked well (in VESA mode), but the NVIDIA is not displaying early boot messages at all. Maybe a vgabios issue. Windows was booting nevertheless - until we installed the NVIDIA drivers. Than it ran into a blue screen. BTW, what ATI adapter did you use precisely, and what did work, what not? One thing I was wondering: Most modern adapters should be PCIe these days. Our NVIDIA definitely is. But so far we are claiming to have it attached to a PCI bus. That caps all the extended capabilities e.g. Could this make some relevant difference? Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux