Patchwork PCI / PM: Restore the original behavior of pci_set_power_state()

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Submitter Rafael J. Wysocki
Date June 28, 2012, 10:01 a.m.
Message ID <201206281201.02414.rjw@sisk.pl>
Download mbox | patch
Permalink /patch/167839/
State Accepted
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Comments

Rafael J. Wysocki - June 28, 2012, 10:01 a.m.
From: Rafael J. Wysocki <rjw@sisk.pl>

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 <rjw@sisk.pl>
---
 drivers/pci/pci-driver.c |   14 ++++++++------
 drivers/pci/pci.c        |   19 ++++++++++++++++++-
 drivers/pci/pci.h        |    1 +
 3 files changed, 27 insertions(+), 7 deletions(-)

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Bjorn Helgaas - July 5, 2012, 9:29 p.m.
On Thu, Jun 28, 2012 at 4:01 AM, Rafael J. Wysocki <rjw@sisk.pl> wrote:
> From: Rafael J. Wysocki <rjw@sisk.pl>
>
> 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 <rjw@sisk.pl>
> ---
>  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.

Bjorn

>  }
>  EXPORT_SYMBOL_GPL(__pci_complete_power_transition);
> @@ -744,6 +757,10 @@ int pci_set_power_state(struct pci_dev *
>                  */
>                 return 0;
>
> +       /* Check if we're already there */
> +       if (dev->current_state == state)
> +               return 0;
> +
>         __pci_start_power_transition(dev, state);
>
>         /* This device is quirked not to be put into D3, so
> Index: linux/drivers/pci/pci-driver.c
> ===================================================================
> --- linux.orig/drivers/pci/pci-driver.c
> +++ linux/drivers/pci/pci-driver.c
> @@ -459,16 +459,17 @@ static int pci_restore_standard_config(s
>         return 0;
>  }
>
> +#endif
> +
> +#ifdef CONFIG_PM_SLEEP
> +
>  static void pci_pm_default_resume_early(struct pci_dev *pci_dev)
>  {
> -       pci_restore_standard_config(pci_dev);
> +       pci_power_up(pci_dev);
> +       pci_restore_state(pci_dev);
>         pci_fixup_device(pci_fixup_resume_early, pci_dev);
>  }
>
> -#endif
> -
> -#ifdef CONFIG_PM_SLEEP
> -
>  /*
>   * Default "suspend" method for devices that have no driver provided suspend,
>   * or not even a driver at all (second part).
> @@ -1050,7 +1051,8 @@ static int pci_pm_runtime_resume(struct
>         if (!pm || !pm->runtime_resume)
>                 return -ENOSYS;
>
> -       pci_pm_default_resume_early(pci_dev);
> +       pci_restore_standard_config(pci_dev);
> +       pci_fixup_device(pci_fixup_resume_early, pci_dev);
>         __pci_enable_wake(pci_dev, PCI_D0, true, false);
>         pci_fixup_device(pci_fixup_resume, pci_dev);
>
> Index: linux/drivers/pci/pci.h
> ===================================================================
> --- linux.orig/drivers/pci/pci.h
> +++ linux/drivers/pci/pci.h
> @@ -67,6 +67,7 @@ struct pci_platform_pm_ops {
>
>  extern int pci_set_platform_pm(struct pci_platform_pm_ops *ops);
>  extern void pci_update_current_state(struct pci_dev *dev, pci_power_t state);
> +extern void pci_power_up(struct pci_dev *dev);
>  extern void pci_disable_enabled_device(struct pci_dev *dev);
>  extern int pci_finish_runtime_suspend(struct pci_dev *dev);
>  extern int __pci_pme_wakeup(struct pci_dev *dev, void *ign);
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Rafael J. Wysocki - July 5, 2012, 9:57 p.m.
On Thursday, July 05, 2012, Bjorn Helgaas wrote:
> On Thu, Jun 28, 2012 at 4:01 AM, Rafael J. Wysocki <rjw@sisk.pl> wrote:
> > From: Rafael J. Wysocki <rjw@sisk.pl>
> >
> > 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 <rjw@sisk.pl>
> > ---
> >  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
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Bjorn Helgaas - July 5, 2012, 10:31 p.m.
On Thu, Jul 5, 2012 at 3:57 PM, Rafael J. Wysocki <rjw@sisk.pl> wrote:
> On Thursday, July 05, 2012, Bjorn Helgaas wrote:
>> On Thu, Jun 28, 2012 at 4:01 AM, Rafael J. Wysocki <rjw@sisk.pl> wrote:
>> > From: Rafael J. Wysocki <rjw@sisk.pl>
>> >
>> > 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 <rjw@sisk.pl>
>> > ---
>> >  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.

Applied to my "next" branch and pushed, thanks a lot!

Bjorn
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Patch

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;
 }
 EXPORT_SYMBOL_GPL(__pci_complete_power_transition);
@@ -744,6 +757,10 @@  int pci_set_power_state(struct pci_dev *
 		 */
 		return 0;
 
+	/* Check if we're already there */
+	if (dev->current_state == state)
+		return 0;
+
 	__pci_start_power_transition(dev, state);
 
 	/* This device is quirked not to be put into D3, so
Index: linux/drivers/pci/pci-driver.c
===================================================================
--- linux.orig/drivers/pci/pci-driver.c
+++ linux/drivers/pci/pci-driver.c
@@ -459,16 +459,17 @@  static int pci_restore_standard_config(s
 	return 0;
 }
 
+#endif
+
+#ifdef CONFIG_PM_SLEEP
+
 static void pci_pm_default_resume_early(struct pci_dev *pci_dev)
 {
-	pci_restore_standard_config(pci_dev);
+	pci_power_up(pci_dev);
+	pci_restore_state(pci_dev);
 	pci_fixup_device(pci_fixup_resume_early, pci_dev);
 }
 
-#endif
-
-#ifdef CONFIG_PM_SLEEP
-
 /*
  * Default "suspend" method for devices that have no driver provided suspend,
  * or not even a driver at all (second part).
@@ -1050,7 +1051,8 @@  static int pci_pm_runtime_resume(struct
 	if (!pm || !pm->runtime_resume)
 		return -ENOSYS;
 
-	pci_pm_default_resume_early(pci_dev);
+	pci_restore_standard_config(pci_dev);
+ 	pci_fixup_device(pci_fixup_resume_early, pci_dev);
 	__pci_enable_wake(pci_dev, PCI_D0, true, false);
 	pci_fixup_device(pci_fixup_resume, pci_dev);
 
Index: linux/drivers/pci/pci.h
===================================================================
--- linux.orig/drivers/pci/pci.h
+++ linux/drivers/pci/pci.h
@@ -67,6 +67,7 @@  struct pci_platform_pm_ops {
 
 extern int pci_set_platform_pm(struct pci_platform_pm_ops *ops);
 extern void pci_update_current_state(struct pci_dev *dev, pci_power_t state);
+extern void pci_power_up(struct pci_dev *dev);
 extern void pci_disable_enabled_device(struct pci_dev *dev);
 extern int pci_finish_runtime_suspend(struct pci_dev *dev);
 extern int __pci_pme_wakeup(struct pci_dev *dev, void *ign);