From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jon Smirl Subject: Monitor failing mode validation in fb_validate_mode() Date: Mon, 25 Apr 2005 13:03:42 -0400 Message-ID: <9e4733910504251003da4d47e@mail.gmail.com> Reply-To: linux-fbdev-devel@lists.sourceforge.net Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Return-path: Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.11] helo=sc8-sf-mx1.sourceforge.net) by sc8-sf-list1.sourceforge.net with esmtp (Exim 4.30) id 1DQ6zv-0003CT-9F for linux-fbdev-devel@lists.sourceforge.net; Mon, 25 Apr 2005 10:03:51 -0700 Received: from wproxy.gmail.com ([64.233.184.204]) by sc8-sf-mx1.sourceforge.net with esmtp (Exim 4.41) id 1DQ6zt-0002a9-TW for linux-fbdev-devel@lists.sourceforge.net; Mon, 25 Apr 2005 10:03:51 -0700 Received: by wproxy.gmail.com with SMTP id 69so1306853wri for ; Mon, 25 Apr 2005 10:03:42 -0700 (PDT) Content-Disposition: inline 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: Benjamin Herrenschmidt , fbdev I have a monitor that in DDC reports that it supports: VESA 1024x768-75 The timing from modesdb.c =09/* 15 1024x768-75 VESA */ =09{ NULL, 75, 1024, 768, 12690, 176, 16, 28, 1, 96, 3, Now multiply out the bandwidth: 1000000000/12690*1000 / (1024 +176 + 16 + 96) gives 60.062 KHz >From DDC the monitor also reports it's bandwidth: Monitor Operating Limits: From EDID H: 30-60KHz V: 50-75Hz DCLK: 80MHz fb_validate_mode() then fails to validate this mode because 60.062Khz is greater than 60KHz I checked and this isn't a round off problem. For the bandwidth to multiply out to below 60KHz the dot clock would need to be 12704 instead of 12690. What is the right fix for this? Maybe truncate (or round) hfreq to the nearest KHz before doing the bandwidth comparison in the bottom of fb_validate_mode()? The dot clock is still well withing range, 78802000 dclkmax 80000000, only the horizontal frequency is a little bit out. Dot clock is probably the hard limit and shouldn't be adjusted. --=20 Jon Smirl jonsmirl@gmail.com ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click