From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Antonino A. Daplas" Subject: Re: can't access video memory? Date: Sat, 10 Sep 2005 13:46:55 +0800 Message-ID: <4322734F.5050407@gmail.com> References: <4321A7D6.9070702@comcast.net> Reply-To: linux-fbdev-devel@lists.sourceforge.net Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.91] helo=mail.sourceforge.net) by sc8-sf-list1.sourceforge.net with esmtp (Exim 4.30) id 1EDyDc-0007Mo-CT for linux-fbdev-devel@lists.sourceforge.net; Fri, 09 Sep 2005 22:48:04 -0700 Received: from zproxy.gmail.com ([64.233.162.200]) by mail.sourceforge.net with esmtp (Exim 4.44) id 1EDyDb-0002bH-1F for linux-fbdev-devel@lists.sourceforge.net; Fri, 09 Sep 2005 22:48:04 -0700 Received: by zproxy.gmail.com with SMTP id i11so15609nzh for ; Fri, 09 Sep 2005 22:47:56 -0700 (PDT) In-Reply-To: <4321A7D6.9070702@comcast.net> Sender: linux-fbdev-devel-admin@lists.sourceforge.net Errors-To: linux-fbdev-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Id: List-Post: List-Help: List-Subscribe: , List-Archive: Content-Type: text/plain; charset="us-ascii" To: linux-fbdev-devel@lists.sourceforge.net Cc: Zack Smith Zack Smith wrote: > Hi all, > > As an experiment I tried accessing a part of (shared) video memory > on my system that is not being used for display data, and this caused the > kernel to crash. I have 6 megs of space and the display is using only half, > but accessing above the 3 meg mark causes the problem. Accessing > the lower 3 megs works fine. > > Does anyone know what might cause this? Depends on the driver. It's possible that the driver did not ioremap the entire graphics aperture (ie ioremapped only the first 3 megs). Or the driver set info->fix.smem_len to only 3 MB instead of 6. Some drivers are now differentiating between remapped size vs actual physical size (radeonfb). info->screen_size, if not zero, tells the amount of the remapped size while info->fix.smem_len, the actual physical size. Tony ------------------------------------------------------- SF.Net email is Sponsored by the Better Software Conference & EXPO September 19-22, 2005 * San Francisco, CA * Development Lifecycle Practices Agile & Plan-Driven Development * Managing Projects & Teams * Testing & QA Security * Process Improvement & Measurement * http://www.sqe.com/bsce5sf