From mboxrd@z Thu Jan 1 00:00:00 1970 From: Aaron Lu Subject: Re: [PATCH] ACPI / PM: Infer parent power state from child if unknown Date: Tue, 11 Sep 2012 13:33:07 +0800 Message-ID: <20120911053305.GA2130@mint-spring.sh.intel.com> References: <1346053126-7646-1-git-send-email-aaron.lu@intel.com> <201209072032.55469.rjw@sisk.pl> <20120910003805.GA1590@mint-spring.sh.intel.com> <201209102150.22738.rjw@sisk.pl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <201209102150.22738.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org To: "Rafael J. Wysocki" Cc: Len Brown , linux-acpi@vger.kernel.org, linux-pm@vger.kernel.org, Aaron Lu , LKML List-Id: linux-acpi@vger.kernel.org On Mon, Sep 10, 2012 at 09:50:22PM +0200, Rafael J. Wysocki wrote: > drivers/acpi/bus.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > Index: linux/drivers/acpi/bus.c > =================================================================== > --- linux.orig/drivers/acpi/bus.c > +++ linux/drivers/acpi/bus.c > @@ -228,7 +228,16 @@ static int __acpi_bus_get_power(struct a > result = psc; > } > /* The test below covers ACPI_STATE_UNKNOWN too. */ > - if (result <= ACPI_STATE_D2) { > + if (result == ACPI_STATE_D0) { Oops, I just realized that the check here is too early if device does not have _PSC but _PRx, its parent will miss the chance to get power state updated :-) Sorry for not spotting this earlier. -Aaron > + /* > + * If we were unsure about the device parent's power state up to > + * this point, the fact that the device is in D0 implies that > + * the parent has to be in D0 too. > + */ > + if (device->parent > + && device->parent->power.state == ACPI_STATE_UNKNOWN) > + device->parent->power.state = ACPI_STATE_D0; > + } else if (result <= ACPI_STATE_D2) { > ; /* Do nothing. */ > } else if (device->power.flags.power_resources) { > int error = acpi_power_get_inferred_state(device, &result);