From mboxrd@z Thu Jan 1 00:00:00 1970 From: Frederic Marmond Subject: Re: writing to the videoram Date: Mon, 16 Jun 2003 08:43:38 +0200 Sender: linux-assembly-owner@vger.kernel.org Message-ID: <3EED671A.9000007@eprocess.fr> References: <00cf01c3336a$92240550$0145a8c0@icepic> Reply-To: fmarmond@eprocess.fr Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <00cf01c3336a$92240550$0145a8c0@icepic> List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: icepic Cc: linux-assembly@vger.kernel.org icepic wrote: >Hi! > >I have a problem. >I want to write directly to the videoram under linux. >Because of the realmode i have some problems.. >can someone explain how it works? > > >- >To unsubscribe from this list: send the line "unsubscribe linux-assembly" in >the body of a message to majordomo@vger.kernel.org >More majordomo info at http://vger.kernel.org/majordomo-info.html > > > realmode ?!? Hey, on which cpu are you??? ;-) I guess you are on x86 architecture, so, some explainations: - x86 have 3 main modes of use: real, virtual and protected (plus a usefull hybrid: flat) - Linux is on protected mode - the bootloader (lilo, grub) make the switch from real mode (when you switch on your PC, it is in real-mode, for 8086 compatibility!) to the protected mode. If you want to write to the video memory, one basic thing would be to write it from the kernel (who have the right to read/write everywhere). From the user-space, you'll have to ask the write access to the kernel. Could you please ask a more precise question?!? Fred