On 4/6/2022 5:36 PM, Rafael J. Wysocki wrote: > On Wednesday, April 6, 2022 7:32:45 AM CEST Abhishek Sahu wrote: >> On 4/5/2022 10:20 PM, Rafael J. Wysocki wrote: >>> On Tuesday, April 5, 2022 6:36:34 PM CEST Abhishek Sahu wrote: >>>> On 2/8/2022 4:00 PM, Abhishek Sahu wrote: >>>>> On 2/8/2022 12:28 AM, Rafael J. Wysocki wrote: >>>>>> On Saturday, February 5, 2022 12:32:19 AM CET Bjorn Helgaas wrote: >>>>>>> [+cc Rafael, hoping for your review :) >>>>>> >>>>>> +Mika >>>>>> >>>>>>> Wonder if we should add something like this to MAINTAINERS so you get >>>>>>> cc'd on power-related things: >>>>>>> >>>>>>> diff --git a/MAINTAINERS b/MAINTAINERS >>>>>>> index ea3e6c914384..3d9a211cad5d 100644 >>>>>>> --- a/MAINTAINERS >>>>>>> +++ b/MAINTAINERS >>>>>>> @@ -15422,6 +15422,7 @@ F: include/linux/pm.h >>>>>>> F: include/linux/pm_* >>>>>>> F: include/linux/powercap.h >>>>>>> F: kernel/configs/nopm.config >>>>>>> +K: pci_[a-z_]*power[a-z_]*\( >>>>>> >>>>>> It seems so, but generally PM patches should be CCed to linux-pm anyway. >>>>>> >>>>>>> >>>>>>> DYNAMIC THERMAL POWER MANAGEMENT (DTPM) >>>>>>> M: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx> >>>>>>> ] >>>>>>> >>>>>>> On Mon, Jan 24, 2022 at 05:51:07PM +0530, Abhishek Sahu wrote: >>>>>>>> Consider the following sequence during PCI device runtime >>>>>>>> suspend/resume: >>>>>>>> >>>>>>>> 1. PCI device goes into runtime suspended state. The PCI state >>>>>>>> will be changed to PCI_D0 and then pci_platform_power_transition() >>>>>>>> will be called which changes the ACPI state to ACPI_STATE_D3_HOT. >>>>>> >>>>>> You mean PCI_D3hot I suppose? >>>>>> >>>>> >>>>> Yes. It should be PCI_D3hot here. >>>>> >>>>>>>> 2. Parent bridge goes into runtime suspended state. If parent >>>>>>>> bridge supports D3cold, then it will change the power state of all its >>>>>>>> children to D3cold state and the power will be removed. >>>>>>>> >>>>>>>> 3. During wake-up time, the bridge will be runtime resumed first >>>>>>>> and pci_power_up() will be called for the bridge. Now, the power >>>>>>>> supply will be resumed. >>>>>>>> >>>>>>>> 4. pci_resume_bus() will be called which will internally invoke >>>>>>>> pci_restore_standard_config(). pci_update_current_state() >>>>>>>> will read PCI_PM_CTRL register and the current_state will be >>>>>>>> updated to D0. >>>>>>>> >>>>>>>> In the above process, at step 4, the ACPI device state will still be >>>>>>>> ACPI_STATE_D3_HOT since pci_platform_power_transition() is not being >>>>>>>> invoked. >>>>>> >>>>>> I'm not quite following. >>>>>> >>>>>> I'm assuming that this description applies to the endpoint device that was >>>>>> previously put into D3_hot. >>>>>> >>>>> >>>>> Yes. This is applicable for endpoint devices which was previously put >>>>> into D3hot. >>>>> >>>>>> Since its current state is D3_hot, it is not D0 (in particular) and the >>>>>> pci_set_power_state() in pci_restore_standard_config() should put int into >>>>>> D0 proper, including the platform firmware part. >>>>>> >>>>> >>>>> The pci_restore_standard_config() for endpoint devices are being called >>>>> internally during wake-up of upstream bridge. >>>>> >>>>> pci_power_up(struct pci_dev *dev) >>>>> { >>>>> ... >>>>> if (dev->runtime_d3cold) { >>>>> /* >>>>> * When powering on a bridge from D3cold, the whole hierarchy >>>>> * may be powered on into D0uninitialized state, resume them to >>>>> * give them a chance to suspend again >>>>> */ >>>>> pci_resume_bus(dev->subordinate); >>>>> } >>>>> ... >>>>> } >>>>> >>>>> For the upstream bridge, the above code will trigger the wake-up of >>>>> endpoint devices and then following code will be executed for the >>>>> endpoint devices: >>>>> >>>>> pci_update_current_state(struct pci_dev *dev, pci_power_t state) >>>>> { >>>>> if (platform_pci_get_power_state(dev) == PCI_D3cold || >>>>> !pci_device_is_present(dev)) { >>>>> dev->current_state = PCI_D3cold; >>>>> } else if (dev->pm_cap) { >>>>> u16 pmcsr; >>>>> >>>>> pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr); >>>>> dev->current_state = (pmcsr & PCI_PM_CTRL_STATE_MASK); >>>>> } else { >>>>> dev->current_state = state; >>>>> } >>>>> } >>>>> >>>>> In the above code, the current_state will be set to D0 for the >>>>> endpoint devices since it will go into second block where >>>>> it will read the PM_CTRL register. >>>>> >>>>>>>> We need call the pci_platform_power_transition() with state >>>>>>>> D0 to change the ACPI state to ACPI_STATE_D0. >>>>>>>> >>>>>>>> This patch calls pci_power_up() if current power state is D0 inside >>>>>>>> pci_restore_standard_config(). This pci_power_up() will change the >>>>>>>> ACPI state to ACPI_STATE_D0. >>>>>>>> >>>>>>>> Following are the steps to confirm: >>>>>>>> >>>>>>>> Enable the debug prints in acpi_pci_set_power_state() >>>>>>>> >>>>>>>> 0000:01:00.0 is PCI device and 0000:00:01.0 is parent bridge device >>>>>>>> >>>>>>>> Before: >>>>>>>> >>>>>>>> 0000:01:00.0: power state changed by ACPI to D3hot >>>>>>>> 0000:00:01.0: power state changed by ACPI to D3cold >>>>>>>> 0000:00:01.0: power state changed by ACPI to D0 >>>>>>>> >>>>>>>> After: >>>>>>>> >>>>>>>> 0000:01:00.0: power state changed by ACPI to D3hot >>>>>>>> 0000:00:01.0: power state changed by ACPI to D3cold >>>>>>>> 0000:00:01.0: power state changed by ACPI to D0 >>>>>>>> 0000:01:00.0: power state changed by ACPI to D0 >>>>>>>> >>>>>>>> So with this patch, the PCI device ACPI state is also being >>>>>>>> changed to D0. >>>>>>>> >>>>>>>> Signed-off-by: Abhishek Sahu <abhsahu@xxxxxxxxxx> >>>>>>>> --- >>>>>>>> drivers/pci/pci-driver.c | 14 +++++++++++--- >>>>>>>> 1 file changed, 11 insertions(+), 3 deletions(-) >>>>>>>> >>>>>>>> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c >>>>>>>> index 588588cfda48..64e0cca12f16 100644 >>>>>>>> --- a/drivers/pci/pci-driver.c >>>>>>>> +++ b/drivers/pci/pci-driver.c >>>>>>>> @@ -521,14 +521,22 @@ static void pci_device_shutdown(struct device *dev) >>>>>>>> */ >>>>>>>> static int pci_restore_standard_config(struct pci_dev *pci_dev) >>>>>>>> { >>>>>>>> + int error = 0; >>>>>>>> pci_update_current_state(pci_dev, PCI_UNKNOWN); >>>>>>>> >>>>>>>> if (pci_dev->current_state != PCI_D0) { >>>>>>>> - int error = pci_set_power_state(pci_dev, PCI_D0); >>>>>>>> - if (error) >>>>>>>> - return error; >>>>>>>> + error = pci_set_power_state(pci_dev, PCI_D0); >>>>>>>> + } else { >>>>>>>> + /* >>>>>>>> + * The platform power state can still be non-D0, so this is >>>>>>>> + * required to change the platform power state to D0. >>>>>>>> + */ >>>>>> >>>>>> This really isn't expected to happen. >>>>>> >>>>>> If the device's power state has been changed to D3hot by ACPI, it is not in D0. >>>>>> >>>>>> It looks like the state tracking is not working here. >>>>>> >>>>> >>>>> The state setting to D0 is happening due to the current logic present in >>>>> pci_update_current_state(). If we can fix the logic in >>>>> pci_update_current_state() to detect this condition and return state D3hot, >>>>> then it should also fix the issue. >>>>> >>>>> Thanks, >>>>> Abhishek >>>>> >>>> >>>> Hi Rafael/Mika, >>>> >>>> Could you please help regarding the correct way to fix this issue. >>>> I can update the patch accordingly. >>> >>> I think you can try one of the patches posted recently: >>> >>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatchwork.kernel.org%2Fproject%2Flinux-pm%2Fpatch%2F3623886.MHq7AAxBmi%40kreacher%2F&data=04%7C01%7Cabhsahu%40nvidia.com%7C87470c4f30f14871bcc708da17c5e913%7C43083d15727340c1b7db39efd9ccc17a%7C0%7C0%7C637848436478123578%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=USJs87Fmm0Vcjm1YWszZCBTpcNQED3InOuOdGgE3f88%3D&reserved=0 >>> >>> Thanks! >>> >>> >>> >> >> Thanks Rafael. >> I have applied both the changes and still the issue which I mentioned is happening. >> >> Following are the prints: >> >> 0000:01:00.0: power state changed by ACPI to D3hot >> 0000:00:01.0: power state changed by ACPI to D3cold >> 0000:00:01.0: power state changed by ACPI to D0 >> >> So ACPI state change is still not happening for PCI endpoint devices. >> >> Also, the I checked the code and the pci_power_up() will not be called >> for endpoint devices. For endpoints, pci_restore_standard_config() will >> be called first where the current state will come as D0. > > OK, I see. > > The problem is that if the PCI device goes to D0 because of the bridge power-up, > it's ACPI companion's power state may not follow, which means that we really > want to do a full power-up in there. > > Please test the appended patch with the patch from > > https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatchwork.kernel.org%2Fproject%2Flinux-pm%2Fpatch%2F3623886.MHq7AAxBmi%40kreacher%2F&data=04%7C01%7Cabhsahu%40nvidia.com%7C87470c4f30f14871bcc708da17c5e913%7C43083d15727340c1b7db39efd9ccc17a%7C0%7C0%7C637848436478123578%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=USJs87Fmm0Vcjm1YWszZCBTpcNQED3InOuOdGgE3f88%3D&reserved=0 > > still applied. > > --- > drivers/pci/pci-driver.c | 2 +- > 1 file changed, 1 insertion(+), 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 > @@ -1312,7 +1312,7 @@ static int pci_pm_runtime_resume(struct > * to a driver because although we left it in D0, it may have gone to > * D3cold when the bridge above it runtime suspended. > */ > - pci_restore_standard_config(pci_dev); > + pci_pm_default_resume_early(pci_dev); > > if (!pci_dev->driver) > return 0; > Thanks Rafael. With the above code change, the issue is getting fixed and the PCI endpoint power state is also changing to D0. 0000:01:00.0: power state changed by ACPI to D3hot 0000:00:01.0: power state changed by ACPI to D3cold 0000:00:01.0: power state changed by ACPI to D0 0000:01:00.0: power state changed by ACPI to D0 Regards, Abhishek