Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261650AbUJYBo4 (ORCPT ); Sun, 24 Oct 2004 21:44:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261657AbUJYBo4 (ORCPT ); Sun, 24 Oct 2004 21:44:56 -0400 Received: from mailgate0.sover.net ([209.198.87.43]:58819 "EHLO mx0.sover.net") by vger.kernel.org with ESMTP id S261650AbUJYBox (ORCPT ); Sun, 24 Oct 2004 21:44:53 -0400 Message-ID: <417C5A91.40008@sover.net> Date: Sun, 24 Oct 2004 21:44:49 -0400 From: Stephen Wille Padnos User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.7.3) Gecko/20040910 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Bodo Eggert <7eggert@gmx.de> CC: linux-kernel@vger.kernel.org, geert@linux-m68k.org Subject: Re: HARDWARE: Open-Source-Friendly Graphics Cards -- Viable? References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1768 Lines: 45 Bodo Eggert wrote: >Geert Uytterhoeven wrote: > > >> <>On Wed, 20 Oct 2004, Jon Smirl wrote: > >>>If you implement VGA you will be able to boot and work in any x86 >>>system without writing any code other than the BIOS. >>> >>> >>Ugh... I prefer _not_ to have VGA compatibility. >> >> >If you want to be able to see the BIOS, you'll need some legacy emulation, >but it should be enough to implement MDA output. > > Nope. The PC BIOS looks for "expansion ROMs", and calls initialization routines in the ones it finds. It then expects to be able to call INT 10 to position the cursor and print text (and read the cursor position, what's on screen, etc.). You could have a BIOS on a network card that provides the necessary interrupt routines, but actually talks to a remote X server for display functions. (yes - it might need to advertise itself as a video device for this to work) >Since some VGA cards used to depend on the MDA/CGA BIOS routines, most >(all?) BIOS variants will implement all nescensary IO functions. You'll >need some MDA registers for the cursor position (that don't even clash with >EGA/VGA/CGA), 4K mapped memory at B000:0000 and a loop translating the text. > > Right - all video cards provide these BIOS routines (including one the one being considered here). They aren't in the system BIOS. (Not that there are no broken BIOSes around, but strictly speaking, there is no need at all for the system BIOS to know anything about the display card being used) - Steve - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/