From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= Subject: Re: [Linux-fbdev-devel] [PATCH] atyfb: fix distorted image on PowerMacs Date: Tue, 3 Feb 2009 20:56:25 +0200 Message-ID: <20090203185624.GC22401@sci.fi> References: <46e1c7760901221022p697f1689ubf03c909cdf1b99b@mail.gmail.com> <20090122201204.GD4996@sci.fi> Mime-Version: 1.0 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: <20090122201204.GD4996@sci.fi> Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="iso-8859-1" To: Risto Suominen , Alex Kern , linux-kernel@vger.kernel.org, benh@kernel.crashing.org, linux-fbdev-devel@lists.sourceforge.net On Thu, Jan 22, 2009 at 10:12:04PM +0200, Ville Syrj=E4l=E4 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 Pow= erMac 5500 > > and PowerMac G3 Beige rev A) with ATI Mach64 chip have suffered fro= m 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 par= ameters to > > be written to the chip. This patch uses a value calculated by aty_i= nit_pll_ct > > instead, as a starting point. >=20 > AFAICS it should be the right thing to do on other systems too. I hav= e > 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. --=20 Ville Syrj=E4l=E4 syrjala@sci.fi http://www.sci.fi/~syrjala/