diff mbox

PCI / PM: Force devices to D0 in pci_pm_thaw_noirq()

Message ID 2582328.YfNXS1jHhG@aspire.rjw.lan (mailing list archive)
State Mainlined
Delegated to: Rafael Wysocki
Headers show

Commit Message

Rafael J. Wysocki Dec. 15, 2017, 2:07 a.m. UTC
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

It is incorrect to call pci_restore_state() for devices in low-power
states (D1-D3), as that involves the restoration of MSI setup which
requires MMIO to be operational and that is only the case in D0.

However, pci_pm_thaw_noirq() may do that if the driver's "freeze"
callbacks put the device into a low-power state, so fix it by making
it force devices into D0 via pci_set_power_state() instead of trying
to "update" their power state which is pointless.

Fixes: e60514bd4485 (PCI/PM: Restore the status of PCI devices across hibernation)
Cc: 4.13+ <stable@vger.kernel.org> # 4.13+
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Maarten Lankhorst <dev@mblankhorst.nl>
Tested-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Maarten Lankhorst <dev@mblankhorst.nl>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

The bug is not as old as I thought, actually.

Yes, we did the pci_update_current_state() in pci_pm_thaw_noirq()
forever, but it started to be problematic in 4.13, when we started
to call pci_restore_state() in addition to it to fix another issue.

---
 drivers/pci/pci-driver.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

Comments

Rafael J. Wysocki Dec. 15, 2017, 2:28 p.m. UTC | #1
On Fri, Dec 15, 2017 at 3:07 AM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> It is incorrect to call pci_restore_state() for devices in low-power
> states (D1-D3), as that involves the restoration of MSI setup which
> requires MMIO to be operational and that is only the case in D0.
>
> However, pci_pm_thaw_noirq() may do that if the driver's "freeze"
> callbacks put the device into a low-power state, so fix it by making
> it force devices into D0 via pci_set_power_state() instead of trying
> to "update" their power state which is pointless.
>
> Fixes: e60514bd4485 (PCI/PM: Restore the status of PCI devices across hibernation)
> Cc: 4.13+ <stable@vger.kernel.org> # 4.13+
> Reported-by: Thomas Gleixner <tglx@linutronix.de>
> Reported-by: Maarten Lankhorst <dev@mblankhorst.nl>
> Tested-by: Thomas Gleixner <tglx@linutronix.de>
> Tested-by: Maarten Lankhorst <dev@mblankhorst.nl>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
>
> The bug is not as old as I thought, actually.
>
> Yes, we did the pci_update_current_state() in pci_pm_thaw_noirq()
> forever, but it started to be problematic in 4.13, when we started
> to call pci_restore_state() in addition to it to fix another issue.

Bjorn, any concerns about this one?

> ---
>  drivers/pci/pci-driver.c |    7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> Index: linux-pm/drivers/pci/pci-driver.c
> ===================================================================
> --- linux-pm.orig/drivers/pci/pci-driver.c
> +++ linux-pm/drivers/pci/pci-driver.c
> @@ -1027,7 +1027,12 @@ static int pci_pm_thaw_noirq(struct devi
>         if (pci_has_legacy_pm_support(pci_dev))
>                 return pci_legacy_resume_early(dev);
>
> -       pci_update_current_state(pci_dev, PCI_D0);
> +       /*
> +        * pci_restore_state() requires the device to be in D0 (because of MSI
> +        * restoration among other things), so force it into D0 in case the
> +        * driver's "freeze" callbacks put it into a low-power state directly.
> +        */
> +       pci_set_power_state(pci_dev, PCI_D0);
>         pci_restore_state(pci_dev);
>
>         if (drv && drv->pm && drv->pm->thaw_noirq)
>
Bjorn Helgaas Dec. 15, 2017, 6:30 p.m. UTC | #2
On Fri, Dec 15, 2017 at 03:07:18AM +0100, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 
> It is incorrect to call pci_restore_state() for devices in low-power
> states (D1-D3), as that involves the restoration of MSI setup which
> requires MMIO to be operational and that is only the case in D0.
> 
> However, pci_pm_thaw_noirq() may do that if the driver's "freeze"
> callbacks put the device into a low-power state, so fix it by making
> it force devices into D0 via pci_set_power_state() instead of trying
> to "update" their power state which is pointless.
> 
> Fixes: e60514bd4485 (PCI/PM: Restore the status of PCI devices across hibernation)
> Cc: 4.13+ <stable@vger.kernel.org> # 4.13+
> Reported-by: Thomas Gleixner <tglx@linutronix.de>
> Reported-by: Maarten Lankhorst <dev@mblankhorst.nl>
> Tested-by: Thomas Gleixner <tglx@linutronix.de>
> Tested-by: Maarten Lankhorst <dev@mblankhorst.nl>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

Let me know if you want me to take this.  I don't have anything
currently queued up that touches pci-driver.c, so I'm happy if you
take it yourself.

> ---
> 
> The bug is not as old as I thought, actually.
> 
> Yes, we did the pci_update_current_state() in pci_pm_thaw_noirq()
> forever, but it started to be problematic in 4.13, when we started
> to call pci_restore_state() in addition to it to fix another issue.
> 
> ---
>  drivers/pci/pci-driver.c |    7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> Index: linux-pm/drivers/pci/pci-driver.c
> ===================================================================
> --- linux-pm.orig/drivers/pci/pci-driver.c
> +++ linux-pm/drivers/pci/pci-driver.c
> @@ -1027,7 +1027,12 @@ static int pci_pm_thaw_noirq(struct devi
>  	if (pci_has_legacy_pm_support(pci_dev))
>  		return pci_legacy_resume_early(dev);
>  
> -	pci_update_current_state(pci_dev, PCI_D0);
> +	/*
> +	 * pci_restore_state() requires the device to be in D0 (because of MSI
> +	 * restoration among other things), so force it into D0 in case the
> +	 * driver's "freeze" callbacks put it into a low-power state directly.
> +	 */
> +	pci_set_power_state(pci_dev, PCI_D0);
>  	pci_restore_state(pci_dev);
>  
>  	if (drv && drv->pm && drv->pm->thaw_noirq)
>
Rafael J. Wysocki Dec. 15, 2017, 11:44 p.m. UTC | #3
On Fri, Dec 15, 2017 at 7:30 PM, Bjorn Helgaas <helgaas@kernel.org> wrote:
> On Fri, Dec 15, 2017 at 03:07:18AM +0100, Rafael J. Wysocki wrote:
>> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>>
>> It is incorrect to call pci_restore_state() for devices in low-power
>> states (D1-D3), as that involves the restoration of MSI setup which
>> requires MMIO to be operational and that is only the case in D0.
>>
>> However, pci_pm_thaw_noirq() may do that if the driver's "freeze"
>> callbacks put the device into a low-power state, so fix it by making
>> it force devices into D0 via pci_set_power_state() instead of trying
>> to "update" their power state which is pointless.
>>
>> Fixes: e60514bd4485 (PCI/PM: Restore the status of PCI devices across hibernation)
>> Cc: 4.13+ <stable@vger.kernel.org> # 4.13+
>> Reported-by: Thomas Gleixner <tglx@linutronix.de>
>> Reported-by: Maarten Lankhorst <dev@mblankhorst.nl>
>> Tested-by: Thomas Gleixner <tglx@linutronix.de>
>> Tested-by: Maarten Lankhorst <dev@mblankhorst.nl>
>> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
>
> Let me know if you want me to take this.  I don't have anything
> currently queued up that touches pci-driver.c, so I'm happy if you
> take it yourself.

I will take it.

Depending of what Yu finds, we may need an additional fix to make the
Purley system work.

>> ---
>>
>> The bug is not as old as I thought, actually.
>>
>> Yes, we did the pci_update_current_state() in pci_pm_thaw_noirq()
>> forever, but it started to be problematic in 4.13, when we started
>> to call pci_restore_state() in addition to it to fix another issue.
>>
>> ---
>>  drivers/pci/pci-driver.c |    7 ++++++-
>>  1 file changed, 6 insertions(+), 1 deletion(-)
>>
>> Index: linux-pm/drivers/pci/pci-driver.c
>> ===================================================================
>> --- linux-pm.orig/drivers/pci/pci-driver.c
>> +++ linux-pm/drivers/pci/pci-driver.c
>> @@ -1027,7 +1027,12 @@ static int pci_pm_thaw_noirq(struct devi
>>       if (pci_has_legacy_pm_support(pci_dev))
>>               return pci_legacy_resume_early(dev);
>>
>> -     pci_update_current_state(pci_dev, PCI_D0);
>> +     /*
>> +      * pci_restore_state() requires the device to be in D0 (because of MSI
>> +      * restoration among other things), so force it into D0 in case the
>> +      * driver's "freeze" callbacks put it into a low-power state directly.
>> +      */
>> +     pci_set_power_state(pci_dev, PCI_D0);
>>       pci_restore_state(pci_dev);
>>
>>       if (drv && drv->pm && drv->pm->thaw_noirq)
>>
diff mbox

Patch

Index: linux-pm/drivers/pci/pci-driver.c
===================================================================
--- linux-pm.orig/drivers/pci/pci-driver.c
+++ linux-pm/drivers/pci/pci-driver.c
@@ -1027,7 +1027,12 @@  static int pci_pm_thaw_noirq(struct devi
 	if (pci_has_legacy_pm_support(pci_dev))
 		return pci_legacy_resume_early(dev);
 
-	pci_update_current_state(pci_dev, PCI_D0);
+	/*
+	 * pci_restore_state() requires the device to be in D0 (because of MSI
+	 * restoration among other things), so force it into D0 in case the
+	 * driver's "freeze" callbacks put it into a low-power state directly.
+	 */
+	pci_set_power_state(pci_dev, PCI_D0);
 	pci_restore_state(pci_dev);
 
 	if (drv && drv->pm && drv->pm->thaw_noirq)