From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Antonino A. Daplas" Subject: Re: VESA, EDID & flat panels Date: Tue, 04 Oct 2005 08:03:57 +0800 Message-ID: <4341C6ED.8080108@gmail.com> References: <1128380013.8267.125.camel@gaston> Reply-To: linux-fbdev-devel@lists.sourceforge.net Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: Received: from sc8-sf-mx2-b.sourceforge.net ([10.3.1.92] helo=mail.sourceforge.net) by sc8-sf-list1.sourceforge.net with esmtp (Exim 4.30) id 1EMaI8-00080a-2N for linux-fbdev-devel@lists.sourceforge.net; Mon, 03 Oct 2005 17:04:20 -0700 Received: from xproxy.gmail.com ([66.249.82.197]) by mail.sourceforge.net with esmtp (Exim 4.44) id 1EMaI5-0006Wf-Gj for linux-fbdev-devel@lists.sourceforge.net; Mon, 03 Oct 2005 17:04:20 -0700 Received: by xproxy.gmail.com with SMTP id i28so287976wxd for ; Mon, 03 Oct 2005 17:04:09 -0700 (PDT) In-Reply-To: <1128380013.8267.125.camel@gaston> 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: Benjamin Herrenschmidt Benjamin Herrenschmidt wrote: > Hi ! > > Somebody around here has access to the VESA specs ? I'm trying to figure > out if the EDID block, at least on recent flat panels, tells us wether > the panel digital input is 6:6:6 or 8:8:8 ... If it's 6:6:6, we should > enable dithering in drivers like radeon and "nv", while if 8:8:8, we > should not. If not enabling it on a 6 bits panel, we end up with crappy > looking gradients, if enabling it on a 8 bits panel, we basically end up > sending a 6 bits signal to a 8 bits panel, thus reducing the quality. > The main 128-byte block of EDID version 1.x does not carry information for that. However, EDID version 1.3 and later support extended 128-byte blocks, and one of them, DI-EXT may carry the information you need. Specifically, section 3.4.5 of this doc might help: http://www.vesa.org/public/EDID%20EXTENSIONS/DIEXT.pdf You will still need to know how to get these extended blocks from i2c. I think vesa's site also has public docs on how to do that. EDID version 2 (which is 256 bytes in size) may also have that information, but I don't know if the specs are freely available. Tony ------------------------------------------------------- This SF.Net email is sponsored by: Power Architecture Resource Center: Free content, downloads, discussions, and more. http://solutions.newsforge.com/ibmarch.tmpl