From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Antonino A. Daplas" Subject: Re: Default timings in vga16fb driver Date: Thu, 25 Nov 2004 00:16:23 +0800 Message-ID: <200411250016.25813.adaplas@hotpop.com> References: <41A36DA5.8090200@fujitsu-siemens.com> Reply-To: linux-fbdev-devel@lists.sourceforge.net Mime-Version: 1.0 Content-Transfer-Encoding: 7bit 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 1CWzpu-0003ta-85 for linux-fbdev-devel@lists.sourceforge.net; Wed, 24 Nov 2004 08:17:42 -0800 Received: from smtp-out.hotpop.com ([38.113.3.71]) by sc8-sf-mx1.sourceforge.net with esmtp (Exim 4.41) id 1CWzpt-0000mW-9d for linux-fbdev-devel@lists.sourceforge.net; Wed, 24 Nov 2004 08:17:42 -0800 Received: from hotpop.com (kubrick.hotpop.com [38.113.3.103]) by smtp-out.hotpop.com (Postfix) with SMTP id 987CB11EC74B for ; Wed, 24 Nov 2004 16:16:30 +0000 (UTC) In-Reply-To: <41A36DA5.8090200@fujitsu-siemens.com> 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: linux-fbdev-devel@lists.sourceforge.net, Martin Wilck On Wednesday 24 November 2004 01:04, Martin Wilck wrote: > Hello, > > I am wondering about the standard mode timings for the 640x480@60 mode > in vga16fb driver (vga16fb_defined): > > .pixclock = 39721, > .left_margin = 48, > .right_margin = 16, > .upper_margin = 39, > .lower_margin = 8, > .hsync_len = 96, > .vsync_len = 2, > .vmode = FB_VMODE_NONINTERLACED, > > IMO this corresponds to a total screen height of 529 which is different > from the value 525 which is normally used (eg in X Windows). What is the > reason for this? Is it possible that the value for "upper_margin" should Possibly, because nobody really complained that the modeline is slightly off. Most users have variable sync displays and should have no problem display a slightly off modeline. > > be 35 rather than 39? > I am asking because we have encountered a video device that obviously > has problems displaying the standard mode of the vga16fb driver. > Did the device work correctly after changing the modeline? > More detail: > > Unless I'm mistaken, the above translates into an XFree86 modeline > ModeLine "640x480" 25.175 640 656 752 800 480 488 490 529 Yes, the above does give a slightly off vert refresh rate of 59.49 (800*529)/25175000 > > The standard XFree86 modeline for this mode, however, looks like this: > (same in drivers/video/modedb.c) > ModeLine "640x480" 25.175 640 664 760 800 480 491 493 525 This one gives a refresh rate of 59.94 which is the closest we can get to a 60 Hz refresh. > > The description at http://www.epanorama.net/documents/pc/vga_timing.html. > would suggest: > ModeLine "640x480" 25.175 640 656 752 800 480 490 492 525 And this one too. > > I apologize if I'm overlooking something. I don't think you overlooked anything. The default modeline of vga16fb should be corrected. Tony ------------------------------------------------------- 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://productguide.itmanagersjournal.com/