From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752964AbZBCS4h (ORCPT ); Tue, 3 Feb 2009 13:56:37 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751387AbZBCS42 (ORCPT ); Tue, 3 Feb 2009 13:56:28 -0500 Received: from smtp4.welho.com ([213.243.153.38]:36961 "EHLO smtp4.welho.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751239AbZBCS42 (ORCPT ); Tue, 3 Feb 2009 13:56:28 -0500 Date: Tue, 3 Feb 2009 20:56:25 +0200 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Risto Suominen , Alex Kern , linux-kernel@vger.kernel.org, benh@kernel.crashing.org, linux-fbdev-devel@lists.sourceforge.net Subject: Re: [Linux-fbdev-devel] [PATCH] atyfb: fix distorted image on PowerMacs Message-ID: <20090203185624.GC22401@sci.fi> Mail-Followup-To: Risto Suominen , Alex Kern , linux-kernel@vger.kernel.org, benh@kernel.crashing.org, linux-fbdev-devel@lists.sourceforge.net References: <46e1c7760901221022p697f1689ubf03c909cdf1b99b@mail.gmail.com> <20090122201204.GD4996@sci.fi> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20090122201204.GD4996@sci.fi> User-Agent: Mutt/1.5.16 (2007-06-09) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 22, 2009 at 10:12:04PM +0200, Ville Syrjälä wrote: > On Thu, Jan 22, 2009 at 08:22:48PM +0200, Risto Suominen wrote: > > Since the complete re-write in 2.6.10, some PowerMacs (At least PowerMac 5500 > > and PowerMac G3 Beige rev A) with ATI Mach64 chip have suffered from unstable > > columns in their framebuffer image. This seems to depend on a value (4) read > > from PLL_EXT_CNTL register, which leads to incorrect DSP config parameters to > > be written to the chip. This patch uses a value calculated by aty_init_pll_ct > > instead, as a starting point. > > AFAICS it should be the right thing to do on other systems too. I have > a good collection of mach64 pci cards and laptops so I'll try to find > some time next week to test that theory on x86. Well, the experiment failed on the first Mobility I tried. The FIFO calculations aren't obvious from the code and there's no mention how to actually calculate them in the programming guide. So I guess special casing powermacs is the best way forward. -- Ville Syrjälä syrjala@sci.fi http://www.sci.fi/~syrjala/