From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Wilson Subject: Re: Regression on GMA965 - display seems to have slow jump changes in brightness Date: Wed, 23 May 2012 09:59:23 +0100 Message-ID: <1337763574_198483@CP5-2952> References: <20120522123058.GB4629@phenom.ffwll.local> <20120522144443.GD4629@phenom.ffwll.local> Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Zdenek Kabelac , Sean Paul Cc: Linux Kernel Mailing List , intel-gfx@lists.freedesktop.org, daniel@ffwll.ch, jbarnes@virtuousgeek.org List-Id: intel-gfx@lists.freedesktop.org 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