Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754457Ab2EWI7v (ORCPT ); Wed, 23 May 2012 04:59:51 -0400 Received: from smtp.fireflyinternet.com ([109.228.6.236]:13896 "EHLO fireflyinternet.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751051Ab2EWI7s (ORCPT ); Wed, 23 May 2012 04:59:48 -0400 X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.66.37; From: Chris Wilson Subject: Re: Regression on GMA965 - display seems to have slow jump changes in brightness To: Zdenek Kabelac , Sean Paul Cc: Linux Kernel Mailing List , intel-gfx@lists.freedesktop.org, daniel@ffwll.ch, jbarnes@virtuousgeek.org In-Reply-To: References: <20120522123058.GB4629@phenom.ffwll.local> <20120522144443.GD4629@phenom.ffwll.local> Date: Wed, 23 May 2012 09:59:23 +0100 X-Originating-IP: 78.156.66.37 Message-ID: <1337763574_198483@CP5-2952> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1401 Lines: 29 On Wed, 23 May 2012 08:59:07 +0200, Zdenek Kabelac wrote: > 2012/5/23 Sean Paul : > > Hmm, seems like your display doesn't like to be downclocked, or rather > > you don't like it to be downclocked :) The reason this patch triggered > > it is because it does a better job of finding a compatible clock. You > > can disable lvds downclocking on the kernel command line by setting > > i915.lvds_downclock=0 > > > > Hmm I've been using i915.lvds_downclock=1 on grub command line, and > haven't noticed any visible problems with 3.3 kernel. So I'd rather > ask if the problematic patch isn't doing downclocking in a wrong way? > Or maybe detection that downclocking is not supported properly is not > correct now ? It is more likely that we did not detect a downclock mode before now and so this is the first time that is being used in anger. (There should be some telltales in drm.debug dmesg) If you are really, really brave you can try http://cgit.freedesktop.org/~ickle/linux-2.6/log/?h=fastboot which only triggers the downclock on a vblank. -Chris -- Chris Wilson, Intel Open Source Technology Centre -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/