[PATCH] PCI: Explicitly put devices into D0 when initializing

[PATCH] PCI: Explicitly put devices into D0 when initializing

[Mario Limonciello]

From: Mario Limonciello <mario.limonciello@amd.com>

AMD BIOS team has root caused an issue that NVME storage failed to come
back from suspend to a lack of a call to _REG when NVME device was probed.

commit 112a7f9c8edbf ("PCI/ACPI: Call _REG when transitioning D-states")
added support for calling _REG when transitioning D-states, but this only
works if the device actually "transitions" D-states.

commit 967577b062417 ("PCI/PM: Keep runtime PM enabled for unbound PCI
devices") added support for runtime PM on PCI devices, but never actually
'explicitly' sets the device to D0.

To make sure that devices are in D0 and that platform methods such as
_REG are called, explicitly set all devices into D0 during initialization.

Fixes: 967577b062417 ("PCI/PM: Keep runtime PM enabled for unbound PCI devices")
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
Note: an earlier internal version of this attempted to do this in local_pci_probe()
but this doesn't affect PCI root ports and we need _REG called on the root ports too.

 drivers/pci/pci.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 53a070394739a..cd87c8370dede 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3266,6 +3266,7 @@ void pci_pm_init(struct pci_dev *dev)
 	pci_read_config_word(dev, PCI_STATUS, &status);
 	if (status & PCI_STATUS_IMM_READY)
 		dev->imm_ready = 1;
+	pci_set_power_state(dev, PCI_D0);
 }
 
 static unsigned long pci_ea_flags(struct pci_dev *dev, u8 prop)
-- 
2.43.0

Re: [PATCH] PCI: Explicitly put devices into D0 when initializing

[Wysocki, Rafael J]

On 4/22/2025 3:38 PM, Mario Limonciello wrote:
> From: Mario Limonciello <mario.limonciello@amd.com>
>
> AMD BIOS team has root caused an issue that NVME storage failed to come
> back from suspend to a lack of a call to _REG when NVME device was probed.
>
> commit 112a7f9c8edbf ("PCI/ACPI: Call _REG when transitioning D-states")
> added support for calling _REG when transitioning D-states, but this only
> works if the device actually "transitions" D-states.
>
> commit 967577b062417 ("PCI/PM: Keep runtime PM enabled for unbound PCI
> devices") added support for runtime PM on PCI devices, but never actually
> 'explicitly' sets the device to D0.
>
> To make sure that devices are in D0 and that platform methods such as
> _REG are called, explicitly set all devices into D0 during initialization.
>
> Fixes: 967577b062417 ("PCI/PM: Keep runtime PM enabled for unbound PCI devices")
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
> ---
> Note: an earlier internal version of this attempted to do this in local_pci_probe()
> but this doesn't affect PCI root ports and we need _REG called on the root ports too.
>
>   drivers/pci/pci.c | 1 +
>   1 file changed, 1 insertion(+)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 53a070394739a..cd87c8370dede 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -3266,6 +3266,7 @@ void pci_pm_init(struct pci_dev *dev)
>   	pci_read_config_word(dev, PCI_STATUS, &status);
>   	if (status & PCI_STATUS_IMM_READY)
>   		dev->imm_ready = 1;
> +	pci_set_power_state(dev, PCI_D0);

I'd rather not do this after enabling runtime PM, but at the same time 
doing it before setting up PM would be rather unsafe.

I'd move the pm_runtime_forbid(), pm_runtime_set_active(), and 
pm_runtime_enable() sequence of calls after the pci_set_power_state() 
call above.


>   }
>   
>   static unsigned long pci_ea_flags(struct pci_dev *dev, u8 prop)

Re: [PATCH] PCI: Explicitly put devices into D0 when initializing

[Rafael J. Wysocki]

On Wed, Apr 23, 2025 at 9:12 PM Wysocki, Rafael J
<rafael.j.wysocki@intel.com> wrote:
>
>
> On 4/22/2025 3:38 PM, Mario Limonciello wrote:
> > From: Mario Limonciello <mario.limonciello@amd.com>
> >
> > AMD BIOS team has root caused an issue that NVME storage failed to come
> > back from suspend to a lack of a call to _REG when NVME device was probed.
> >
> > commit 112a7f9c8edbf ("PCI/ACPI: Call _REG when transitioning D-states")
> > added support for calling _REG when transitioning D-states, but this only
> > works if the device actually "transitions" D-states.
> >
> > commit 967577b062417 ("PCI/PM: Keep runtime PM enabled for unbound PCI
> > devices") added support for runtime PM on PCI devices, but never actually
> > 'explicitly' sets the device to D0.
> >
> > To make sure that devices are in D0 and that platform methods such as
> > _REG are called, explicitly set all devices into D0 during initialization.
> >
> > Fixes: 967577b062417 ("PCI/PM: Keep runtime PM enabled for unbound PCI devices")
> > Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
> > ---
> > Note: an earlier internal version of this attempted to do this in local_pci_probe()
> > but this doesn't affect PCI root ports and we need _REG called on the root ports too.
> >
> >   drivers/pci/pci.c | 1 +
> >   1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> > index 53a070394739a..cd87c8370dede 100644
> > --- a/drivers/pci/pci.c
> > +++ b/drivers/pci/pci.c
> > @@ -3266,6 +3266,7 @@ void pci_pm_init(struct pci_dev *dev)
> >       pci_read_config_word(dev, PCI_STATUS, &status);
> >       if (status & PCI_STATUS_IMM_READY)
> >               dev->imm_ready = 1;
> > +     pci_set_power_state(dev, PCI_D0);
>
> I'd rather not do this after enabling runtime PM, but at the same time
> doing it before setting up PM would be rather unsafe.
>
> I'd move the pm_runtime_forbid(), pm_runtime_set_active(), and
> pm_runtime_enable() sequence of calls after the pci_set_power_state()
> call above.

Also, I think that pci_pm_power_up_and_verify_state() would be more
suitable for this initial power up because power_state is already 0 at
this point and this case is analogous  to post-resume.