From mboxrd@z Thu Jan 1 00:00:00 1970 From: Petr Vandrovec Subject: Re: Bug in vga16fb? Date: Thu, 06 Apr 2006 00:48:48 +0200 Message-ID: <44344950.9090703@vc.cvut.cz> References: <20060404204002.GB2251@localhost.localdomain> 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 ([10.3.1.91] helo=mail.sourceforge.net) by sc8-sf-list1.sourceforge.net with esmtp (Exim 4.30) id 1FRGo2-0006S0-N3 for linux-fbdev-devel@lists.sourceforge.net; Wed, 05 Apr 2006 15:48:54 -0700 Received: from mailgw.cvut.cz ([147.32.3.235]) by mail.sourceforge.net with esmtp (Exim 4.44) id 1FRGo1-0006vS-FY for linux-fbdev-devel@lists.sourceforge.net; Wed, 05 Apr 2006 15:48:54 -0700 Received: from mailgw (localhost [127.0.0.1]) by mailgw.cvut.cz (Postfix) with SMTP id 33CCB13B726 for ; Thu, 6 Apr 2006 00:48:49 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by mailgw.cvut.cz (Postfix) with ESMTP id 1A7F813B7F2 for ; Thu, 6 Apr 2006 00:48:49 +0200 (CEST) Received: from mailgw.cvut.cz ([127.0.0.1]) by localhost (mailgw [127.0.0.1]) (amavisd-new, port 10024) with LMTP id 12993-01-33 for ; Thu, 6 Apr 2006 00:48:49 +0200 (CEST) Received: from [127.0.0.1] (buk.vc.cvut.cz [147.32.240.88]) by mailgw.cvut.cz (Postfix) with ESMTP id E73BA13B726 for ; Thu, 6 Apr 2006 00:48:48 +0200 (CEST) In-Reply-To: <20060404204002.GB2251@localhost.localdomain> 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"; format="flowed" To: linux-fbdev-devel@lists.sourceforge.net Ondrej Zajicek wrote: > Hello > > I tried vga16fb driver in 320x200x4 nonstd mode (on i386 - little endian). In > this mode framebuffer reports PACKED PIXELS type. Drawing through framebuffer > is OK, but console is broken - it looks like that even and odd columns are > exchanged. > > Framebuffer structure of this mode is that even pixel is in high nibble and > odd pixel is in low nibble. > > It looks like vga16fb use cfbimgblt.c/slow_imageblit in this mode for > image-blit and this function in CFB4 writes even pixel in low nibble and > odd pixel in high nibble. > > What is correct framebuffer structure for CFB4 mode? Unfortunately there is no standard, as CFB4 itself is quite non-standard VGA mode. Some videocards first output low nibble, followed by high, and some do otherwise. I've experimented with this back in 2000, and I've found that Matrox Millennium does exactly opposite than some ATI Mach64 card I had in another box at that time. So your only option is providing two CFB4 modes. Unfortunately I have no idea how to autodetect what your hardware actually does without adding camera to the system... Petr Vandrovec ------------------------------------------------------- This SF.Net email is sponsored by xPML, a groundbreaking scripting language that extends applications into web and mobile media. Attend the live webcast and join the prime developer group breaking into this new coding territory! http://sel.as-us.falkag.net/sel?cmd=lnk&kid=110944&bid=241720&dat=121642