From mboxrd@z Thu Jan 1 00:00:00 1970 From: "arun c" Subject: Re: How to implement rotation for framebuffer? Date: Tue, 8 Apr 2008 10:33:36 +0530 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" 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-new.sourceforge.net with esmtp (Exim 4.43) id 1Jj5zd-0001SS-3i for linux-fbdev-devel@lists.sourceforge.net; Mon, 07 Apr 2008 22:03:37 -0700 Received: from yw-out-1718.google.com ([74.125.46.154]) by mail.sourceforge.net with esmtp (Exim 4.44) id 1Jj5zc-0006lB-PH for linux-fbdev-devel@lists.sourceforge.net; Mon, 07 Apr 2008 22:03:37 -0700 Received: by yw-out-1718.google.com with SMTP id 4so302398ywq.82 for ; Mon, 07 Apr 2008 22:03:36 -0700 (PDT) In-Reply-To: Content-Disposition: inline List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-fbdev-devel-bounces@lists.sourceforge.net Errors-To: linux-fbdev-devel-bounces@lists.sourceforge.net To: linux-fbdev-devel@lists.sourceforge.net Cc: Geert Uytterhoeven On Fri, Apr 4, 2008 at 4:04 PM, Geert Uytterhoeven wrote: > On Fri, 4 Apr 2008, arun c wrote: > > I am working on 2430SDP. SDP has omap2430 as the processor and it's > > display controller supports rotation of framebuffer in hardware. > > > > I will explain the hardware rotation in brief. > > > > 1) One Physical framebuffer is allocated in memory > > 2) This physical address ( as well as width and height) is programmed in the > > VRFB Module (the hardware rotation engine, it stands for virtual rotated > > frame buffer) > > 3)Then VRFB gives you 4 addresses ( virtual addresses which are > > transparent to applications) > > VBA0 --> Address for 0 degree rotation > > VBA90 --> Address for 90 degree rotation > > VBA180 --> Address for 180 degree rotation > > VBA270 --> Address for 270 degree rotation > > > > Rotation is achieved like this > > Assume you want 90 degree rotation > > > > Processor writes all picture data to VBA90 space and lcd reads all > > data from VBA0 space > > > > For this kind of implementation i need to change fb_fix_screeninfo > > members (smem_start ,smem_len) and fb_info member( screen_base) > > dynamically according to degree of rotation. > > Yep, that's correct. > > > > Please anybody suggest me good ways to implement this kind of > > rotation in my driver or point me to some code so that i can refer and > > implement the same. > > Very simple: any change of struct fb_var_screeninfo may cause a change > of fb_fix_screeninfo. > > Hence if an application requests to change the rotation angle by > changing fb_var_screeninfo.rotate and issuing an FBIOPUT_VSCREENINFO > ioctl, you update your fb_fix_screeninfo and fb_info.screen_base. I was thinking this kind of implementation is not permissible ( I am very much ignorant about fbdev applications), because i thought dynamically changing these structure members make applications to brake. Could anybody please suggest me some example code to refer? Regards, Arun C > > Gr{oetje,eeting}s, > > Geert ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Register now and save $200. Hurry, offer ends at 11:59 p.m., Monday, April 7! Use priority code J8TLD2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone