From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zhang Rui Subject: Re: [RFC] i915/acpi: add lid status notification and detection Date: Thu, 21 May 2009 16:57:53 +0800 Message-ID: <1242896273.32574.10.camel@rzhang-dt> References: <20090513115734.338b7d55@jbarnes-g45> <1242264144.3773.415.camel@localhost.localdomain> <20090519171545.GA17801@srcf.ucam.org> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from mga09.intel.com ([134.134.136.24]:14544 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750820AbZEUI5S (ORCPT ); Thu, 21 May 2009 04:57:18 -0400 In-Reply-To: <20090519171545.GA17801@srcf.ucam.org> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Matthew Garrett Cc: "Zhao, Yakui" , Jesse Barnes , "intel-gfx@lists.freedesktop.org" , "linux-acpi@vger.kernel.org" On Wed, 2009-05-20 at 01:15 +0800, Matthew Garrett wrote: > > > There's also a policy question here. On some machines, a lid close > > > will cause the ACPI firmware to program the GPU, disabling the pipe > > > associated with the panel. Should we detect this and turn it back on > > > at open time? That could be dangerous if userspace has received the > > > LVDS hotplug event and changed the config out from under us... > > > > > > Comments? > > It seems that the LID status is used to determine whether the LVDS is > > connected. > > It is not reliable. On some boxes the initial LID status is incorrect. > > Maybe the LID status is open. But the ACPI returns that the LID is > > close. In such case the LVDS is not initialized and user can't get the > > output. > > Really? I haven't seen any cases of this. They'll fail in all sorts of > fun ways with modern userland. > This is rare, and if this happens, a bug should be filed against ACPI. BTW: we have fixed/root caused all such kind of bugs that have been reported. So I think it makes sense to trust the Lid state reported by ACPI button driver. thanks, rui