From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keith Packard Subject: Re: Broken LVDS output at mode changes Date: Thu, 29 Mar 2012 09:57:41 -0700 Message-ID: <86398rny4a.fsf@sumi.keithp.com> References: <20120329121638.GA20275@phenom.ffwll.local> <1333025081_141778@CP5-2952> <86d37vo38m.fsf@sumi.keithp.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from keithp.com (home.keithp.com [63.227.221.253]) by gabe.freedesktop.org (Postfix) with ESMTP id 5CB789F3B1 for ; Thu, 29 Mar 2012 09:57:45 -0700 (PDT) In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org Errors-To: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org To: Takashi Iwai Cc: intel-gfx@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org <#part sign=pgpmime> On Thu, 29 Mar 2012 18:12:56 +0200, Takashi Iwai wrote: > The strange thing is that, although you can recover the display by > turning off LVDS and on again once when the problem happens, but then > the display starts flickering. And, the flickering continues even > after reboot on BIOS boot screen. Yeah, it's clearly the panel which is confused. It would be nice to know what happened to the LVDS signal which caused this problem with the panel. > BTW, now I tested to disable LVDS unconditionally on different > platforms as Daniel suggested. All worked fine, and I saw no > regressions. Tested on IVY, SNB, ILK, GM45 and PineView. That's not surprising -- pre-PCH platforms disabled the LVDS anyways. I wonder if we could fix this by being more careful about the order of register operations during LVDS mode setting... -- keith.packard@intel.com