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 14:27:28 +0800 Message-ID: <434220D0.3020101@gmail.com> References: <1128380013.8267.125.camel@gaston> <8a0c36780510031618m48c55f45u648d867bcf0130d2@mail.gmail.com> <1128397436.31063.0.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 1EMgHI-0002q8-Do for linux-fbdev-devel@lists.sourceforge.net; Mon, 03 Oct 2005 23:27:52 -0700 Received: from xproxy.gmail.com ([66.249.82.195]) by mail.sourceforge.net with esmtp (Exim 4.44) id 1EMgHF-0000bj-Vm for linux-fbdev-devel@lists.sourceforge.net; Mon, 03 Oct 2005 23:27:52 -0700 Received: by xproxy.gmail.com with SMTP id s7so301689wxc for ; Mon, 03 Oct 2005 23:27:44 -0700 (PDT) In-Reply-To: <1128397436.31063.0.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: > On Mon, 2005-10-03 at 18:18 -0500, Richard Smith wrote: >>> 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. >> We have a copy from a few years ago. Its not too descriptive if >> IIRC. I'll try to look at it tomorrow. > > I found a lot of stuff on VESA Public site in fact. Looks like we really > need to write some infrastructure to get to the EDID extensions :) They > contain all sort of useful infos, though unfortunately, all of the > panels I've come accross so far didn't seem to implement them =P > It think it's because the (basic) EDID is retrieved with (basic) DDC (address 0x50). If I'm not mistaken, E-EDID is retrieved with E-DDC (address 0xa0). I don't exactly know the protocol (E-DDDC specs are not freely available), but try probing your i2c busses with: i2cdump 0,1,2,etc 0xa0 and see if you get anything. Tony ------------------------------------------------------- This SF.Net email is sponsored by: Power Architecture Resource Center: Free content, downloads, discussions, and more. http://solutions.newsforge.com/ibmarch.tmpl