From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Wu Subject: Re: [Resend][PATCH] ACPI / PM: Do not power manage devices in unknown initial states Date: Fri, 01 Feb 2013 19:23:52 +0100 Message-ID: <2135454.ENo8eA9AXp@al> References: <3676077.i6vcpp7Nrn@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <3676077.i6vcpp7Nrn@vostro.rjw.lan> Sender: linux-kernel-owner@vger.kernel.org To: "Rafael J. Wysocki" Cc: ACPI Devel Maling List , LKML , Len Brown , Mika Westerberg List-Id: linux-acpi@vger.kernel.org On Thursday 31 January 2013 23:32:40 Rafael J. Wysocki wrote: > In general, for ACPI device power management to work, the initial > power states of devices must be known (otherwise, we wouldn't be able > to keep track of power resources, for example). Hence, if it is > impossible to determine the initial ACPI power states of some > devices, they can't be regarded as power-manageable using ACPI. > > For this reason, modify acpi_bus_get_power_flags() to clear the > power_manageable flag if acpi_bus_init_power() fails and add some > extra fallback code to acpi_bus_init_power() to cover broken > BIOSes that provide _PS0/_PS3 without _PSC for some devices. > > Verified to work on my HP nx6325 that has this problem. > > Signed-off-by: Rafael J. Wysocki Tested-by: Peter Wu I applied it on top of branch linux-next of repo linux-pm. Fixes the issue I had with bbswitch in Linux 3.8. Can a backport patch be made available for 3.8? Regards, Peter