From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263254AbVHFQvC (ORCPT ); Sat, 6 Aug 2005 12:51:02 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263263AbVHFQvC (ORCPT ); Sat, 6 Aug 2005 12:51:02 -0400 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:21386 "EHLO ebiederm.dsl.xmission.com") by vger.kernel.org with ESMTP id S263254AbVHFQvB (ORCPT ); Sat, 6 Aug 2005 12:51:01 -0400 To: Luca Falavigna Cc: rdunlap@osdl.org, fastboot@osdl.org, Linux Kernel Mailing List Subject: Re: kexec and frame buffer References: <42F219B3.6090502@gmail.com> <42F4C6E8.1050605@gmail.com> From: ebiederm@xmission.com (Eric W. Biederman) Date: Sat, 06 Aug 2005 10:50:25 -0600 In-Reply-To: <42F4C6E8.1050605@gmail.com> (Luca Falavigna's message of "Sat, 06 Aug 2005 14:19:20 +0000") Message-ID: User-Agent: Gnus/5.1007 (Gnus v5.10.7) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Luca Falavigna writes: > Eric W. Biederman ha scritto: >> So without doing passing --real-mode the vga= parameter currently >> cannot work. The vga= parameter is processed by vga.S which >> make BIOS calls and we bypass all of the BIOS calls. > Actually that file is video.S Oops. Anyway I believe you also want to look at include/linux/tty.h at the screen_info structure. I believe that is where all of that information is passed. >> So you can try with the --real-mode option and you have >> a chance of the code working. Or you can figure out which >> information video.S passes to the kernel figure out how >> to get that same information out of a running kernel >> and then /sbin/kexec can be tweaked to pass the current >> video mode. Changing frame buffer modes shouldn't work >> but you should at least be able to preserve the existing >> ones. > I tried to pass --real-mode flag to kexec but my virtual machine doesn't like > it. When I launch kexec -e, it tells me: "A strange behaviour occourred which > crashed virtual machine". Cool. I haven't used that code in a long time but it is pretty trivial code to switches to real mode so I don't really doubt it :) > I'll dig source code ASAP to figure out this matter. > Meanwhile I'm going to follow your advice to inspect video.S in order to track > down something useful. Sounds good. Eric