From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ogre.sisk.pl ([193.178.161.156]:55179 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756214Ab2GEVwM (ORCPT ); Thu, 5 Jul 2012 17:52:12 -0400 From: "Rafael J. Wysocki" To: Bjorn Helgaas Subject: Re: [PATCH] PCI / PM: Restore the original behavior of pci_set_power_state() Date: Thu, 5 Jul 2012 23:57:44 +0200 Cc: Jesse Barnes , Linux PM mailing list , LKML , Matthew Garrett , "linux-pci" , Huang Ying References: <201206281201.02414.rjw@sisk.pl> In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Message-Id: <201207052357.44494.rjw@sisk.pl> Sender: linux-pci-owner@vger.kernel.org List-ID: On Thursday, July 05, 2012, Bjorn Helgaas wrote: > On Thu, Jun 28, 2012 at 4:01 AM, Rafael J. Wysocki wrote: > > From: Rafael J. Wysocki > > > > Commit cc2893b6 (PCI: Ensure we re-enable devices on resume) > > addressed the problem with USB not being powered after resume on > > recent Lenovo machines, but it did that in a suboptimal way. > > Namely, it should have changed the relevant code paths only, > > which are pci_pm_resume_noirq() and pci_pm_restore_noirq() supposed > > to restore the device's power and standard configuration registers > > after system resume from suspend or hibernation. Instead, however, > > it modified pci_set_power_state() which is executed in several > > other situations too. That resulted in some undesirable effects, > > like attempting to change a device's power state in the same way > > multiple times in a row (up to as many as 4 times in a row in the > > snd_hda_intel driver). > > > > Fix the bug addressed by commit cc2893b6 in an alternative way, > > by forcibly powering up all devices in pci_pm_default_resume_early(), > > which is called by pci_pm_resume_noirq() and pci_pm_restore_noirq() > > to restore the device's power and standard configuration registers, > > and modifying pci_pm_runtime_resume() to avoid the forcible power-up > > if not necessary. Then, revert the changes made by commit cc2893b6 > > to make the confusion introduced by it go away. > > > > Signed-off-by: Rafael J. Wysocki > > --- > > drivers/pci/pci-driver.c | 14 ++++++++------ > > drivers/pci/pci.c | 19 ++++++++++++++++++- > > drivers/pci/pci.h | 1 + > > 3 files changed, 27 insertions(+), 7 deletions(-) > > > > Index: linux/drivers/pci/pci.c > > =================================================================== > > --- linux.orig/drivers/pci/pci.c > > +++ linux/drivers/pci/pci.c > > @@ -662,6 +662,19 @@ void pci_update_current_state(struct pci > > } > > > > /** > > + * pci_power_up - Put the given device into D0 forcibly > > + * @dev: PCI device to power up > > + */ > > +void pci_power_up(struct pci_dev *dev) > > +{ > > + if (platform_pci_power_manageable(dev)) > > + platform_pci_set_power_state(dev, PCI_D0); > > + > > + pci_raw_set_power_state(dev, PCI_D0); > > + pci_update_current_state(dev, PCI_D0); > > +} > > + > > +/** > > * pci_platform_power_transition - Use platform to change device power state > > * @dev: PCI device to handle. > > * @state: State to put the device into. > > @@ -707,7 +720,7 @@ static void __pci_start_power_transition > > */ > > int __pci_complete_power_transition(struct pci_dev *dev, pci_power_t state) > > { > > - return state >= PCI_D0 ? > > + return state > PCI_D0 ? > > pci_platform_power_transition(dev, state) : -EINVAL; > > This hunk conflicted with Huang's D3_COLD patches. I fixed it up; can > you check and make sure I did it correctly? > > I pushed the resolution to here: > git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git on the > pci/rafael-pci_set_power_state-rebase branch. Yes, it looks good. The point is to make __pci_complete_power_transition() return the error code for PCI_DO too. Thanks, Rafael