From mboxrd@z Thu Jan 1 00:00:00 1970 From: Geert Uytterhoeven Subject: Re: How to implement rotation for framebuffer? Date: Fri, 4 Apr 2008 12:34:08 +0200 (CEST) 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 1JhjFN-0006YJ-E1 for linux-fbdev-devel@lists.sourceforge.net; Fri, 04 Apr 2008 03:34:13 -0700 Received: from wilson.telenet-ops.be ([195.130.132.42]) by mail.sourceforge.net with esmtp (Exim 4.44) id 1JhjFL-0004Ak-Ph for linux-fbdev-devel@lists.sourceforge.net; Fri, 04 Apr 2008 03:34:13 -0700 In-Reply-To: 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: arun c Cc: linux-fbdev-devel@lists.sourceforge.net 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. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace