From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brian Kress Subject: Re: kvm-84 -- Cirrus video updates bad on XP Date: Sat, 21 Feb 2009 10:53:56 -0500 Message-ID: <49A02394.4010702@moose.net> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: Duck Return-path: Received: from smtprelay0182.hostedemail.com ([216.40.44.182]:44611 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751163AbZBUQOI (ORCPT ); Sat, 21 Feb 2009 11:14:08 -0500 Received: from smtprelay.hostedemail.com (ff-bigip1 [10.5.19.254]) by smtpgrave03.hostedemail.com (Postfix) with ESMTP id E31241BD0AE for ; Sat, 21 Feb 2009 15:55:12 +0000 (UTC) In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: Two seperate problems. The Cirrus VGA issue is due to it trying to be clever about video to video copies, which is why you see it during scrolling and window dragging. I posted patch that (sort of) fixes it, but doesn't completely. This whole area of code is doing something very iffy and getting it to do it correctly seems very hard. The std vga issue is because when the framebuffer is 32 bits (std vga is 32, cirrus vga is 24), the vga driver ends up sharing the vram framebuffer with the display surface. This is interesting and means less copying, however it doesn't seem to be safe, as you end up with the display driver reading memory out of vram and the same time as the guest is writing to it. Hence you end up with weirdness. -Brian Duck wrote: > Patchy video updates also seems to happen, though less obviously, with > '-vga std'. > > For example, I started an XP guest with 'vga std' and then forgot about it > for some time. When I next looked at it, the screen saver had kicked in > (the jumping "Windows" logo) but only the bottom half of the logo was > visible as it bounced around. > > Host is Linux 2.6.27.7 with kvm drivers built from the kvm-84 source tree. > Guest is XP0. > > Haven't seen this behaviour with kvm-83. > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >