From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Wu Subject: Re: [PATCH] ACPI / PM: Add check preventing transitioning to non-D0 state from D3. Date: Wed, 30 Jan 2013 18:53:46 +0100 Message-ID: <4595012.aPT9n2OZdk@al> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: Received: from mail-wi0-f176.google.com ([209.85.212.176]:54823 "EHLO mail-wi0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751573Ab3A3Rxu (ORCPT ); Wed, 30 Jan 2013 12:53:50 -0500 Received: by mail-wi0-f176.google.com with SMTP id hm14so2871961wib.3 for ; Wed, 30 Jan 2013 09:53:49 -0800 (PST) In-Reply-To: Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Lv Zheng Cc: Len Brown , Rafael J Wysocki , linux-acpi@vger.kernel.org Hi Lv Zheng, I encounter a regression with your patch (Linux 3.8-rc5). On my Nvidia Optimus laptop, I use the bbswitch[1] kernel module to trigger a _PS3 ACPI method call to turn the video card off. After this patch, I got the following in my kernel log: pci 0000:01:00.0: Refused to change power state, currently in D0 ACPI: Cannot transition to non-D0 state from D3 bbswitch: Succesfully loaded. Discrete card 0000:01:00.0 is on The expected output would be "Discrete card 0000:01:00.0 is off". Printing the contents of (acpi_device) device->power.state shows FF (ACPI_STATE_UNKNOWN). Should this condition be excluded from your check or is my hacky module outdated? I currently workaround this issue by checking for ACPI_STATE_UNKNOWN. If that is the value, I assume on (overwrite device->power.state with ACPI_STATE_D0). Then I call pci_set_power_state(pci_dev, PCI_D3cold). Regards, Peter [1]: https://github.com/Bumblebee-Project/bbswitch On Thursday 15 November 2012 12:25:01 Lv Zheng wrote: > No power transitioning from D3 state to a non-D0 state is allowed. > This patch also cleans up device power updating code in the > acpi_device_set_power() as it should already been updated in the > acpi_power_transition(). > > Signed-off-by: Lv Zheng > --- > drivers/acpi/bus.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c > index 07a20ee..12c1b51 100644 > --- a/drivers/acpi/bus.c > +++ b/drivers/acpi/bus.c > @@ -293,6 +293,12 @@ int acpi_device_set_power(struct acpi_device *device, > int state) " state than parent\n"); > return -ENODEV; > } > + if (device->parent->power.state >= ACPI_STATE_D3_HOT && > + state != ACPI_STATE_D0) { > + printk(KERN_WARNING PREFIX > + "Cannot transition to non-D0 state from D3\n"); > + return -ENODEV; > + } > > /* For D3cold we should execute _PS3, not _PS4. */ > if (state == ACPI_STATE_D3_COLD) > @@ -341,7 +347,6 @@ int acpi_device_set_power(struct acpi_device *device, > int state) "Device [%s] failed to transition to %s\n", > device->pnp.bus_id, state_string(state)); > else { > - device->power.state = state; > ACPI_DEBUG_PRINT((ACPI_DB_INFO, > "Device [%s] transitioned to %s\n", > device->pnp.bus_id, state_string(state)));