From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1LNV0b-0002F5-IH for qemu-devel@nongnu.org; Thu, 15 Jan 2009 11:23:53 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1LNV0Z-0002Dw-V1 for qemu-devel@nongnu.org; Thu, 15 Jan 2009 11:23:53 -0500 Received: from [199.232.76.173] (port=33796 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1LNV0Z-0002Dq-Pk for qemu-devel@nongnu.org; Thu, 15 Jan 2009 11:23:51 -0500 Received: from mail2.shareable.org ([80.68.89.115]:40908) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1LNV0Z-0001mN-8v for qemu-devel@nongnu.org; Thu, 15 Jan 2009 11:23:51 -0500 Date: Thu, 15 Jan 2009 16:23:47 +0000 From: Jamie Lokier Subject: Re: [Qemu-devel] [PATCH] [RFC] Variable video ram size option Message-ID: <20090115162347.GA5440@shareable.org> References: <496B965A.9000701@eu.citrix.com> <200901142007.42812.paul@codesourcery.com> <496E4E00.3060105@eu.citrix.com> <200901142130.00991.paul@codesourcery.com> <496E6B93.2080107@eu.citrix.com> <20090115130848.GB32368@shareable.org> <5E237914-B830-420A-99BE-4C1959DDFC66@exactcode.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <5E237914-B830-420A-99BE-4C1959DDFC66@exactcode.de> Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Paul Brook Rene Rebe wrote: > >I think the Linux "vesafb" driver uses all available VRAM for > >scrolling in draws-text-on-graphic-framebuffer mode. > > But only with ypan enabled, which wasn't the default when I took a > look the last time. That's right. I don't know why "ypan" is off by default; it's hard to imagine it not working on anything vaguely VBE-like, or even VESA (pre-VBE), since a lot of DOS games need the panning feature to work for double/triple buffering. If you're using Linux guest with VESA framebuffer console, rather than a text-mode console, I'd recommend kernel boot option "video=vesafb:ypan", to save considerable CPU when scrolling the console. I don't know if "video=vesafb:ywrap" works on the QEMU VBE emulation. That'd be better. -- Jamie > -- René Rebe - ExactCODE GmbH - Europe, Germany, Berlin > http://exactcode.de | http://t2-project.org | http://rene.rebe.name