From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keith Packard Subject: Re: [PATCH 1/2] drm/i915: Check VBIOS value for determining LVDS dual channel mode, too Date: Tue, 20 Mar 2012 07:57:14 -0700 Message-ID: <86mx7bmib9.fsf@sumi.keithp.com> References: <1332155257-17649-1-git-send-email-tiwai@suse.de> <1332155257-17649-2-git-send-email-tiwai@suse.de> <20120320094114.GA3951@phenom.ffwll.local> 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 BD25FA09FC for ; Tue, 20 Mar 2012 07:57:20 -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 , Daniel Vetter Cc: intel-gfx@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org <#part sign=pgpmime> On Tue, 20 Mar 2012 13:04:41 +0100, Takashi Iwai wrote: > Since checking the lid state is tricky and unreliable, the practical > check would be simply reading the first LVDS reg and seeing whether it > was initialized or not. It seems that it reads to 0x02 when booted > with the lid close, which is LVDS_DETECTED bit. Right, lid-detect is not useful, so I suggested using the new code path only if the LVDS was *not* actually running at startup time. That should avoid almost all common cases that work correctly today. -- keith.packard@intel.com