From owner-freebsd-current@FreeBSD.ORG Mon Sep 15 17:47:04 2008 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 721D8106564A for ; Mon, 15 Sep 2008 17:47:04 +0000 (UTC) (envelope-from unixmania@gmail.com) Received: from mail-gx0-f17.google.com (mail-gx0-f17.google.com [209.85.217.17]) by mx1.freebsd.org (Postfix) with ESMTP id 138998FC0A for ; Mon, 15 Sep 2008 17:47:03 +0000 (UTC) (envelope-from unixmania@gmail.com) Received: by gxk10 with SMTP id 10so23969273gxk.19 for ; Mon, 15 Sep 2008 10:47:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:cc:in-reply-to:mime-version:content-type :content-transfer-encoding:content-disposition:references; bh=LERLyM+s+goE5k3uhQr5ZyBjZ4wEOayAri3Ig5Sldt4=; b=D4I7aaZpVnH3LG1F3Ts1Yurg4ySHI78fcOMISIARQu4WDD/vMX720W20sop2jpKpNo 5keWrN8VvOTdXzBIst9s5cHNSMt52346cQI1p5r1zkwePwJY5gxVT60dEZIqlH/jK3/k eiHLGgRpOQJPXbugjr917YowCAZN2b623jb9k= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=EkidV91lGXfYuJiZqzVHIG83ZCT5MASC/a32OM5k3MqZRIeMPibZKij8QY1bpVvc9j us42lZKysKIs77XfHwCdID9n7yyotJsm93dWFrAvt5xlWAJODXW2aJQ4ETEPB70g9w0P 4tjaKcrBDhWSez+l6fFHtU3CqBW6lqvtrecAc= Received: by 10.103.200.9 with SMTP id c9mr5709828muq.11.1221499450581; Mon, 15 Sep 2008 10:24:10 -0700 (PDT) Received: by 10.103.231.14 with HTTP; Mon, 15 Sep 2008 10:24:10 -0700 (PDT) Message-ID: Date: Mon, 15 Sep 2008 14:24:10 -0300 From: "Carlos A. M. dos Santos" To: "Jung-uk Kim" In-Reply-To: <200809151232.36756.jkim@FreeBSD.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <200809150922.m8F9MaHg090579@haluter.fromme.com> <200809151232.36756.jkim@FreeBSD.org> Cc: Xin LI , freebsd-current@freebsd.org, Oliver Fromme Subject: Re: Why VESA and DPMS are available only for i386? X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 15 Sep 2008 17:47:04 -0000 On Mon, Sep 15, 2008 at 1:32 PM, Jung-uk Kim wrote: > On Monday 15 September 2008 05:22 am, Oliver Fromme wrote: >> Carlos A. M. dos Santos wrote: >> > Xin LI wrote: >> > > Carlos A. M. dos Santos wrote: >> > > > Several PRs were closed based on the argument that >> > > > FreeBSD/amd64 cannot call to the VESA BIOS. XFree86 solved >> > > > this problem by means of the INT10 module. I believe that it >> > > > would be possible to do the same on the FreeBSD kernel. >> > > > >> > > > Is there any ongoing effort to enable the VESA kernel moule >> > > > on non-i386 platform? Is there any particular difficulty for >> > > > doing this, besides depending on VM86? >> > > >> > > According to VESA's VBE 3.0 standard, there is a "Protected >> > > Mode Entry Point" [optionally] provided by BIOS, which OS or >> > > application is supposed to copy to a place where it is >> > > writable. The code there would be written in 16-bit protected >> > > mode. Therefore I think it's do-able... >> > > >> > > http://www.vesa.org/public/VBE/vbe3.pdf >> > >> > I'm reading the specification and digging at the code of the X >> > server and the X VESA driver. Look promising. >> >> Don't hold your breath. Peter explained that this is more >> involved than it seems at first glance: >> >> http://lists.freebsd.org/pipermail/freebsd-amd64/2005-October/00637 >>6.html >> >> Here's a quote: >> | [FreeBSD's VESA code] is trying to use bios calls to change >> | the modes. This is something a 64 bit kernel cannot do. To >> | make this work, one would have to trampoline out of 64 bit mode >> | and into 32 bit mode, then do the vm86 or bios32() calls. This >> | is more work than it might appear at first because you have to >> | deal with interrupts. One would have to write a 32 bit >> | mini-kernel that can accept interrupts and traps, trampoline to >> | 64 bit mode, handle them, then return, switching back to 32 bit >> | mode. All with page tables etc. And of course you have to do >> | extra data copying and have a way to describe it to the API. >> >> By the way, It doesn't matter whether you use the VESA >> BIOS' real-mode functions or the protected-mode functions >> (which exist since VBE 2.0, not only 3.0). From the view >> of an amd64 kernel it doesn't make a difference. >> >> Another way would be to write a 32bit x86 instruction >> emulator (similar to what programs like qemu or bochs do), >> so you can execute the VESA functions within an emulated >> virtual machine that programs the VGA hardware registers. >> This isn't exactly trivial either. Note that there are >> already such emulators, but I'm not aware of a BSD-licensed >> one that could be included in the FreeBSD kernel without >> problems. > > doscmd(1) had a rudimentary 16-bit CPU emulation: > > http://www.freebsd.org/cgi/cvsweb.cgi/projects/doscmd/ > http://www.freebsd.org/cgi/cvsweb.cgi/projects/doscmd/cpu.c No change in the last 4 years. Is there anybody responsible for it these days? -- cd /usr/ports/sysutils/life make clean