[PATCH 0/4] Add support for drivers to decide bridge D3 policy

[PATCH 0/4] Add support for drivers to decide bridge D3 policy

[Mario Limonciello]

The policy for whether PCI bridges are allowed to select D3 is dictated
by empirical results that are enumerated into pci_bridge_d3_possible().

In Windows this behaves differently in that Windows internal policy is
not used for devices when a power engine plugin driver provided by the
SOC vendor is installed.  This driver is used to decide the policy in
those cases.

This series implements a system that lets drivers register such a policy
control as well. It isn't activated for any SOCs by default.

This is heavily leveraged from the work in [1]

[1] https://lore.kernel.org/platform-driver-x86/20230906184354.45846-1-mario.limonciello@amd.com/

RFC v1->PATCH v1
 * Simplify the logic, use pci_d3cold_enable()/pci_d3cold_disable() functions
 * Roll https://lore.kernel.org/linux-pci/20231004144731.158342-1-mario.limonciello@amd.com/ into series
 * Updates for some typos
 * Re-order series.  Patches 1 and 2 can potentially apply to PCI tree, 3 and 4 to platform-x86 tree.

Mario Limonciello (4):
  PCI: Make d3cold_allowed sysfs attribute read only
  PCI: Refresh root ports in pci_bridge_d3_update()
  ACPI: x86: s2idle: Export symbol for fetching constraints for module
    use
  platform/x86/amd: pmc: Add support for using constraints to decide D3
    policy

 Documentation/ABI/testing/sysfs-bus-pci |  4 +-
 drivers/acpi/x86/s2idle.c               |  1 +
 drivers/pci/pci-acpi.c                  |  2 +-
 drivers/pci/pci-sysfs.c                 | 14 +-----
 drivers/pci/pci.c                       | 12 ++++--
 drivers/platform/x86/amd/pmc/pmc.c      | 57 +++++++++++++++++++++++++
 include/linux/pci.h                     |  1 -
 7 files changed, 72 insertions(+), 19 deletions(-)

-- 
2.34.1

[PATCH 1/4] PCI: Make d3cold_allowed sysfs attribute read only

[Mario Limonciello]

Before kernel 3.6 D3cold was considered "opt-in" for PCIe devices.
Userspace was able to opt PCIe devices into d3cold support by using
the `d3cold_allowed` sysfs attribute. The policy changed to default
to enabled with commit 4f9c1397e2e8 ("PCI/PM: Enable D3/D3cold by
default for most devices").  The sysfs file remains however and
can potentially allow userspace to prevent the SoC from getting into
the deepest sleep state on modern systems.

For debugging purposes `pcie_port_pm=` can be used to control whether
a PCI port will go into D3cold and runtime PM can be turned off by
`/sys/bus/pci/devices/*/power/control` on PCI end points.

Change the sysfs attribute to a noop that ignores the input when written
and shows a warning. Simplify the internal kernel logic to drop
`d3cold_allowed`.

Link: https://lore.kernel.org/linux-pci/20230918132424.GA11357@wunner.de/
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
Changes from previous submission:
 * Update commit message
 * Roll into series for D3 related handling
---
 Documentation/ABI/testing/sysfs-bus-pci |  4 ++--
 drivers/pci/pci-acpi.c                  |  2 +-
 drivers/pci/pci-sysfs.c                 | 14 ++------------
 drivers/pci/pci.c                       |  3 +--
 include/linux/pci.h                     |  1 -
 5 files changed, 6 insertions(+), 18 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
index ecf47559f495..b5db141dfee6 100644
--- a/Documentation/ABI/testing/sysfs-bus-pci
+++ b/Documentation/ABI/testing/sysfs-bus-pci
@@ -283,8 +283,8 @@ Description:
 		device will never be put into D3Cold state.  If it is set, the
 		device may be put into D3Cold state if other requirements are
 		satisfied too.  Reading this attribute will show the current
-		value of d3cold_allowed bit.  Writing this attribute will set
-		the value of d3cold_allowed bit.
+		value of no_d3cold bit.
+		Writing to this attribute is deprecated and will do nothing.
 
 What:		/sys/bus/pci/devices/.../sriov_totalvfs
 Date:		November 2012
diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index 05b7357bd258..a05350a4e49c 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -911,7 +911,7 @@ pci_power_t acpi_pci_choose_state(struct pci_dev *pdev)
 {
 	int acpi_state, d_max;
 
-	if (pdev->no_d3cold || !pdev->d3cold_allowed)
+	if (pdev->no_d3cold)
 		d_max = ACPI_STATE_D3_HOT;
 	else
 		d_max = ACPI_STATE_D3_COLD;
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 5e741a05cf2c..52ed5a55a371 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -523,17 +523,7 @@ static ssize_t d3cold_allowed_store(struct device *dev,
 				    struct device_attribute *attr,
 				    const char *buf, size_t count)
 {
-	struct pci_dev *pdev = to_pci_dev(dev);
-	unsigned long val;
-
-	if (kstrtoul(buf, 0, &val) < 0)
-		return -EINVAL;
-
-	pdev->d3cold_allowed = !!val;
-	pci_bridge_d3_update(pdev);
-
-	pm_runtime_resume(dev);
-
+	dev_warn_once(dev, "pci: writing to d3cold_allowed is deprecated\n");
 	return count;
 }
 
@@ -541,7 +531,7 @@ static ssize_t d3cold_allowed_show(struct device *dev,
 				   struct device_attribute *attr, char *buf)
 {
 	struct pci_dev *pdev = to_pci_dev(dev);
-	return sysfs_emit(buf, "%u\n", pdev->d3cold_allowed);
+	return sysfs_emit(buf, "%u\n", !pdev->no_d3cold);
 }
 static DEVICE_ATTR_RW(d3cold_allowed);
 #endif
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 59c01d68c6d5..8c5a6f68f63d 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3067,7 +3067,7 @@ static int pci_dev_check_d3cold(struct pci_dev *dev, void *data)
 	bool *d3cold_ok = data;
 
 	if (/* The device needs to be allowed to go D3cold ... */
-	    dev->no_d3cold || !dev->d3cold_allowed ||
+	    dev->no_d3cold ||
 
 	    /* ... and if it is wakeup capable to do so from D3cold. */
 	    (device_may_wakeup(&dev->dev) &&
@@ -3204,7 +3204,6 @@ void pci_pm_init(struct pci_dev *dev)
 	dev->d3hot_delay = PCI_PM_D3HOT_WAIT;
 	dev->d3cold_delay = PCI_PM_D3COLD_WAIT;
 	dev->bridge_d3 = pci_bridge_d3_possible(dev);
-	dev->d3cold_allowed = true;
 
 	dev->d1_support = false;
 	dev->d2_support = false;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 8c7c2c3c6c65..5f4ed71d31f5 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -376,7 +376,6 @@ struct pci_dev {
 	unsigned int	no_d1d2:1;	/* D1 and D2 are forbidden */
 	unsigned int	no_d3cold:1;	/* D3cold is forbidden */
 	unsigned int	bridge_d3:1;	/* Allow D3 for bridge */
-	unsigned int	d3cold_allowed:1;	/* D3cold is allowed by user */
 	unsigned int	mmio_always_on:1;	/* Disallow turning off io/mem
 						   decoding during BAR sizing */
 	unsigned int	wakeup_prepared:1;
-- 
2.34.1

[PATCH 2/4] PCI: Refresh root ports in pci_bridge_d3_update()

[Mario Limonciello]

If pci_d3cold_enable() or pci_d3cold_disable() is called on a root
port it is ignored because there is no upstream bridge.

If called on a root port, use `no_d3cold` variable to decide policy
and also immediately refresh whether D3 is possible.

Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
Changes from RFC v1:
 * New patch
---
 drivers/pci/pci.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 8c5a6f68f63d..28f70e8ea478 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3021,6 +3021,9 @@ bool pci_bridge_d3_possible(struct pci_dev *bridge)
 		if (pci_bridge_d3_disable)
 			return false;
 
+		if (bridge->no_d3cold)
+			return false;
+
 		/*
 		 * Hotplug ports handled by firmware in System Management Mode
 		 * may not be put into D3 by the OS (Thunderbolt on non-Macs).
@@ -3096,7 +3099,11 @@ void pci_bridge_d3_update(struct pci_dev *dev)
 	bool d3cold_ok = true;
 
 	bridge = pci_upstream_bridge(dev);
-	if (!bridge || !pci_bridge_d3_possible(bridge))
+	if (!bridge) {
+		dev->bridge_d3 = pci_bridge_d3_possible(dev);
+		return;
+	}
+	if (!pci_bridge_d3_possible(bridge))
 		return;
 
 	/*
-- 
2.34.1

[PATCH 3/4] ACPI: x86: s2idle: Export symbol for fetching constraints for module use

[Mario Limonciello]

The amd-pmc driver will be fetching constraints to make decisions at
suspend time. This driver can be compiled as a module, so export the
symbol for when it is a module.

Acked-by: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
 drivers/acpi/x86/s2idle.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/acpi/x86/s2idle.c b/drivers/acpi/x86/s2idle.c
index 08f7c6708206..de9c313c21fa 100644
--- a/drivers/acpi/x86/s2idle.c
+++ b/drivers/acpi/x86/s2idle.c
@@ -322,6 +322,7 @@ int acpi_get_lps0_constraint(struct acpi_device *adev)
 
 	return ACPI_STATE_UNKNOWN;
 }
+EXPORT_SYMBOL_GPL(acpi_get_lps0_constraint);
 
 static void lpi_check_constraints(void)
 {
-- 
2.34.1

[PATCH 4/4] platform/x86/amd: pmc: Add support for using constraints to decide D3 policy

[Mario Limonciello]

The default kernel policy will allow modern machines to effectively put
all PCIe bridges into PCI D3. This policy doesn't match what Windows uses.

In Windows the driver stack includes a "Power Engine Plugin" (uPEP driver)
to decide the policy for integrated devices using PEP device constraints.

Device constraints are expressed as a number in the _DSM of the PNP0D80
device and exported by the kernel in acpi_get_lps0_constraint().

Add support for SoCs to use constraints on Linux as well for deciding
target state for integrated PCI bridges.

Disable existing production SoCs by default with this change.

Link: https://learn.microsoft.com/en-us/windows-hardware/design/device-experiences/platform-design-for-modern-standby#low-power-core-silicon-cpu-soc-dram
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
Changes from RFC v1:
 * Use pci_d3cold_*able() instead
---
 drivers/platform/x86/amd/pmc/pmc.c | 57 ++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)

diff --git a/drivers/platform/x86/amd/pmc/pmc.c b/drivers/platform/x86/amd/pmc/pmc.c
index c1e788b67a74..346564517667 100644
--- a/drivers/platform/x86/amd/pmc/pmc.c
+++ b/drivers/platform/x86/amd/pmc/pmc.c
@@ -741,6 +741,61 @@ static int amd_pmc_czn_wa_irq1(struct amd_pmc_dev *pdev)
 	return 0;
 }
 
+static inline void amd_pmc_apply_constraint(struct pci_dev *pci_dev, bool apply)
+{
+	if (apply)
+		pci_d3cold_disable(pci_dev);
+	else
+		pci_d3cold_enable(pci_dev);
+}
+
+/*
+ * Constraints are specified in the ACPI LPS0 device and specify what the
+ * platform intended for devices that are internal to the SoC.
+ *
+ * If a constraint is present and >= to ACPI_STATE_D3, then enable D3.
+ * If a constraint is not present or < ACPI_STATE_D3, then disable D3.
+ */
+static void amd_pmc_check_constraints(struct amd_pmc_dev *pdev, bool apply)
+{
+	struct pci_dev *pci_dev = NULL;
+	struct acpi_device *adev;
+	int constraint;
+
+	switch (pdev->cpu_id) {
+	case AMD_CPU_ID_RV:
+	case AMD_CPU_ID_RN:
+	case AMD_CPU_ID_YC:
+	case AMD_CPU_ID_CB:
+	case AMD_CPU_ID_PS:
+	case AMD_CPU_ID_SP:
+		return;
+	default:
+		break;
+	}
+
+	while ((pci_dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, pci_dev))) {
+		adev = ACPI_COMPANION(&pci_dev->dev);
+		if (!adev)
+			continue;
+		constraint = acpi_get_lps0_constraint(adev);
+		dev_dbg(&pci_dev->dev, "constraint is %d\n", constraint);
+
+		switch (constraint) {
+		case ACPI_STATE_UNKNOWN:
+		case ACPI_STATE_D0:
+		case ACPI_STATE_D1:
+		case ACPI_STATE_D2:
+			amd_pmc_apply_constraint(pci_dev, apply);
+			continue;
+		/* use the logic pci_bridge_d3_possible() to decide */
+		case ACPI_STATE_D3:
+		default:
+			continue;
+		}
+	}
+}
+
 static int amd_pmc_verify_czn_rtc(struct amd_pmc_dev *pdev, u32 *arg)
 {
 	struct rtc_device *rtc_device;
@@ -1074,6 +1129,7 @@ static int amd_pmc_probe(struct platform_device *pdev)
 			amd_pmc_quirks_init(dev);
 	}
 
+	amd_pmc_check_constraints(dev, TRUE);
 	amd_pmc_dbgfs_register(dev);
 	pm_report_max_hw_sleep(U64_MAX);
 	return 0;
@@ -1089,6 +1145,7 @@ static void amd_pmc_remove(struct platform_device *pdev)
 
 	if (IS_ENABLED(CONFIG_SUSPEND))
 		acpi_unregister_lps0_dev(&amd_pmc_s2idle_dev_ops);
+	amd_pmc_check_constraints(dev, FALSE);
 	amd_pmc_dbgfs_unregister(dev);
 	pci_dev_put(dev->rdev);
 	mutex_destroy(&dev->lock);
-- 
2.34.1

Re: [PATCH 1/4] PCI: Make d3cold_allowed sysfs attribute read only

[Rafael J. Wysocki]

On Wednesday, October 25, 2023 4:05:43 AM CEST Mario Limonciello wrote:
> Before kernel 3.6 D3cold was considered "opt-in" for PCIe devices.
> Userspace was able to opt PCIe devices into d3cold support by using
> the `d3cold_allowed` sysfs attribute. The policy changed to default
> to enabled with commit 4f9c1397e2e8 ("PCI/PM: Enable D3/D3cold by
> default for most devices").  The sysfs file remains however and
> can potentially allow userspace to prevent the SoC from getting into
> the deepest sleep state on modern systems.
> 
> For debugging purposes `pcie_port_pm=` can be used to control whether
> a PCI port will go into D3cold and runtime PM can be turned off by
> `/sys/bus/pci/devices/*/power/control` on PCI end points.
> 
> Change the sysfs attribute to a noop that ignores the input when written
> and shows a warning. Simplify the internal kernel logic to drop
> `d3cold_allowed`.
> 
> Link: https://lore.kernel.org/linux-pci/20230918132424.GA11357@wunner.de/
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>

I'm not aware of anyone using this sysfs i/f in practice, so

Acked-by: Rafael J. Wysocki <rafael@kernel.org>

> ---
> Changes from previous submission:
>  * Update commit message
>  * Roll into series for D3 related handling
> ---
>  Documentation/ABI/testing/sysfs-bus-pci |  4 ++--
>  drivers/pci/pci-acpi.c                  |  2 +-
>  drivers/pci/pci-sysfs.c                 | 14 ++------------
>  drivers/pci/pci.c                       |  3 +--
>  include/linux/pci.h                     |  1 -
>  5 files changed, 6 insertions(+), 18 deletions(-)
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
> index ecf47559f495..b5db141dfee6 100644
> --- a/Documentation/ABI/testing/sysfs-bus-pci
> +++ b/Documentation/ABI/testing/sysfs-bus-pci
> @@ -283,8 +283,8 @@ Description:
>  		device will never be put into D3Cold state.  If it is set, the
>  		device may be put into D3Cold state if other requirements are
>  		satisfied too.  Reading this attribute will show the current
> -		value of d3cold_allowed bit.  Writing this attribute will set
> -		the value of d3cold_allowed bit.
> +		value of no_d3cold bit.
> +		Writing to this attribute is deprecated and will do nothing.
>  
>  What:		/sys/bus/pci/devices/.../sriov_totalvfs
>  Date:		November 2012
> diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
> index 05b7357bd258..a05350a4e49c 100644
> --- a/drivers/pci/pci-acpi.c
> +++ b/drivers/pci/pci-acpi.c
> @@ -911,7 +911,7 @@ pci_power_t acpi_pci_choose_state(struct pci_dev *pdev)
>  {
>  	int acpi_state, d_max;
>  
> -	if (pdev->no_d3cold || !pdev->d3cold_allowed)
> +	if (pdev->no_d3cold)
>  		d_max = ACPI_STATE_D3_HOT;
>  	else
>  		d_max = ACPI_STATE_D3_COLD;
> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> index 5e741a05cf2c..52ed5a55a371 100644
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
> @@ -523,17 +523,7 @@ static ssize_t d3cold_allowed_store(struct device *dev,
>  				    struct device_attribute *attr,
>  				    const char *buf, size_t count)
>  {
> -	struct pci_dev *pdev = to_pci_dev(dev);
> -	unsigned long val;
> -
> -	if (kstrtoul(buf, 0, &val) < 0)
> -		return -EINVAL;
> -
> -	pdev->d3cold_allowed = !!val;
> -	pci_bridge_d3_update(pdev);
> -
> -	pm_runtime_resume(dev);
> -
> +	dev_warn_once(dev, "pci: writing to d3cold_allowed is deprecated\n");
>  	return count;
>  }
>  
> @@ -541,7 +531,7 @@ static ssize_t d3cold_allowed_show(struct device *dev,
>  				   struct device_attribute *attr, char *buf)
>  {
>  	struct pci_dev *pdev = to_pci_dev(dev);
> -	return sysfs_emit(buf, "%u\n", pdev->d3cold_allowed);
> +	return sysfs_emit(buf, "%u\n", !pdev->no_d3cold);
>  }
>  static DEVICE_ATTR_RW(d3cold_allowed);
>  #endif
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 59c01d68c6d5..8c5a6f68f63d 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -3067,7 +3067,7 @@ static int pci_dev_check_d3cold(struct pci_dev *dev, void *data)
>  	bool *d3cold_ok = data;
>  
>  	if (/* The device needs to be allowed to go D3cold ... */
> -	    dev->no_d3cold || !dev->d3cold_allowed ||
> +	    dev->no_d3cold ||
>  
>  	    /* ... and if it is wakeup capable to do so from D3cold. */
>  	    (device_may_wakeup(&dev->dev) &&
> @@ -3204,7 +3204,6 @@ void pci_pm_init(struct pci_dev *dev)
>  	dev->d3hot_delay = PCI_PM_D3HOT_WAIT;
>  	dev->d3cold_delay = PCI_PM_D3COLD_WAIT;
>  	dev->bridge_d3 = pci_bridge_d3_possible(dev);
> -	dev->d3cold_allowed = true;
>  
>  	dev->d1_support = false;
>  	dev->d2_support = false;
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 8c7c2c3c6c65..5f4ed71d31f5 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -376,7 +376,6 @@ struct pci_dev {
>  	unsigned int	no_d1d2:1;	/* D1 and D2 are forbidden */
>  	unsigned int	no_d3cold:1;	/* D3cold is forbidden */
>  	unsigned int	bridge_d3:1;	/* Allow D3 for bridge */
> -	unsigned int	d3cold_allowed:1;	/* D3cold is allowed by user */
>  	unsigned int	mmio_always_on:1;	/* Disallow turning off io/mem
>  						   decoding during BAR sizing */
>  	unsigned int	wakeup_prepared:1;
> 

Re: [PATCH 0/4] Add support for drivers to decide bridge D3 policy

[Rafael J. Wysocki]

On Wednesday, October 25, 2023 4:05:42 AM CEST Mario Limonciello wrote:
> The policy for whether PCI bridges are allowed to select D3 is dictated
> by empirical results that are enumerated into pci_bridge_d3_possible().
> 
> In Windows this behaves differently in that Windows internal policy is
> not used for devices when a power engine plugin driver provided by the
> SOC vendor is installed.  This driver is used to decide the policy in
> those cases.
> 
> This series implements a system that lets drivers register such a policy
> control as well. It isn't activated for any SOCs by default.
> 
> This is heavily leveraged from the work in [1]
> 
> [1] https://lore.kernel.org/platform-driver-x86/20230906184354.45846-1-mario.limonciello@amd.com/
> 
> RFC v1->PATCH v1
>  * Simplify the logic, use pci_d3cold_enable()/pci_d3cold_disable() functions
>  * Roll https://lore.kernel.org/linux-pci/20231004144731.158342-1-mario.limonciello@amd.com/ into series
>  * Updates for some typos
>  * Re-order series.  Patches 1 and 2 can potentially apply to PCI tree, 3 and 4 to platform-x86 tree.
> 
> Mario Limonciello (4):
>   PCI: Make d3cold_allowed sysfs attribute read only
>   PCI: Refresh root ports in pci_bridge_d3_update()
>   ACPI: x86: s2idle: Export symbol for fetching constraints for module
>     use
>   platform/x86/amd: pmc: Add support for using constraints to decide D3
>     policy
> 
>  Documentation/ABI/testing/sysfs-bus-pci |  4 +-
>  drivers/acpi/x86/s2idle.c               |  1 +
>  drivers/pci/pci-acpi.c                  |  2 +-
>  drivers/pci/pci-sysfs.c                 | 14 +-----
>  drivers/pci/pci.c                       | 12 ++++--
>  drivers/platform/x86/amd/pmc/pmc.c      | 57 +++++++++++++++++++++++++
>  include/linux/pci.h                     |  1 -
>  7 files changed, 72 insertions(+), 19 deletions(-)

Any chance to CC this series to linux-pm and linux-acpi?

Re: [PATCH 0/4] Add support for drivers to decide bridge D3 policy

[Mario Limonciello]

On 10/26/2023 12:04, Rafael J. Wysocki wrote:
> On Wednesday, October 25, 2023 4:05:42 AM CEST Mario Limonciello wrote:
>> The policy for whether PCI bridges are allowed to select D3 is dictated
>> by empirical results that are enumerated into pci_bridge_d3_possible().
>>
>> In Windows this behaves differently in that Windows internal policy is
>> not used for devices when a power engine plugin driver provided by the
>> SOC vendor is installed.  This driver is used to decide the policy in
>> those cases.
>>
>> This series implements a system that lets drivers register such a policy
>> control as well. It isn't activated for any SOCs by default.
>>
>> This is heavily leveraged from the work in [1]
>>
>> [1] https://lore.kernel.org/platform-driver-x86/20230906184354.45846-1-mario.limonciello@amd.com/
>>
>> RFC v1->PATCH v1
>>   * Simplify the logic, use pci_d3cold_enable()/pci_d3cold_disable() functions
>>   * Roll https://lore.kernel.org/linux-pci/20231004144731.158342-1-mario.limonciello@amd.com/ into series
>>   * Updates for some typos
>>   * Re-order series.  Patches 1 and 2 can potentially apply to PCI tree, 3 and 4 to platform-x86 tree.
>>
>> Mario Limonciello (4):
>>    PCI: Make d3cold_allowed sysfs attribute read only
>>    PCI: Refresh root ports in pci_bridge_d3_update()
>>    ACPI: x86: s2idle: Export symbol for fetching constraints for module
>>      use
>>    platform/x86/amd: pmc: Add support for using constraints to decide D3
>>      policy
>>
>>   Documentation/ABI/testing/sysfs-bus-pci |  4 +-
>>   drivers/acpi/x86/s2idle.c               |  1 +
>>   drivers/pci/pci-acpi.c                  |  2 +-
>>   drivers/pci/pci-sysfs.c                 | 14 +-----
>>   drivers/pci/pci.c                       | 12 ++++--
>>   drivers/platform/x86/amd/pmc/pmc.c      | 57 +++++++++++++++++++++++++
>>   include/linux/pci.h                     |  1 -
>>   7 files changed, 72 insertions(+), 19 deletions(-)
> 
> Any chance to CC this series to linux-pm and linux-acpi?
> 
> 
> 
> 

Sure if it needs to spin again I'll send it to those lists as well.

Here's a lore link for you for now though if you want to respond to the 
other patches.

https://lore.kernel.org/platform-driver-x86/0cd6648d-21f1-445d-95f6-20f580bbcfd1@amd.com/T/

Re: [PATCH 0/4] Add support for drivers to decide bridge D3 policy

[Rafael J. Wysocki]

On Thursday, October 26, 2023 7:06:13 PM CEST Mario Limonciello wrote:
> On 10/26/2023 12:04, Rafael J. Wysocki wrote:
> > On Wednesday, October 25, 2023 4:05:42 AM CEST Mario Limonciello wrote:
> >> The policy for whether PCI bridges are allowed to select D3 is dictated
> >> by empirical results that are enumerated into pci_bridge_d3_possible().
> >>
> >> In Windows this behaves differently in that Windows internal policy is
> >> not used for devices when a power engine plugin driver provided by the
> >> SOC vendor is installed.  This driver is used to decide the policy in
> >> those cases.
> >>
> >> This series implements a system that lets drivers register such a policy
> >> control as well. It isn't activated for any SOCs by default.
> >>
> >> This is heavily leveraged from the work in [1]
> >>
> >> [1] https://lore.kernel.org/platform-driver-x86/20230906184354.45846-1-mario.limonciello@amd.com/
> >>
> >> RFC v1->PATCH v1
> >>   * Simplify the logic, use pci_d3cold_enable()/pci_d3cold_disable() functions
> >>   * Roll https://lore.kernel.org/linux-pci/20231004144731.158342-1-mario.limonciello@amd.com/ into series
> >>   * Updates for some typos
> >>   * Re-order series.  Patches 1 and 2 can potentially apply to PCI tree, 3 and 4 to platform-x86 tree.
> >>
> >> Mario Limonciello (4):
> >>    PCI: Make d3cold_allowed sysfs attribute read only
> >>    PCI: Refresh root ports in pci_bridge_d3_update()
> >>    ACPI: x86: s2idle: Export symbol for fetching constraints for module
> >>      use
> >>    platform/x86/amd: pmc: Add support for using constraints to decide D3
> >>      policy
> >>
> >>   Documentation/ABI/testing/sysfs-bus-pci |  4 +-
> >>   drivers/acpi/x86/s2idle.c               |  1 +
> >>   drivers/pci/pci-acpi.c                  |  2 +-
> >>   drivers/pci/pci-sysfs.c                 | 14 +-----
> >>   drivers/pci/pci.c                       | 12 ++++--
> >>   drivers/platform/x86/amd/pmc/pmc.c      | 57 +++++++++++++++++++++++++
> >>   include/linux/pci.h                     |  1 -
> >>   7 files changed, 72 insertions(+), 19 deletions(-)
> > 
> > Any chance to CC this series to linux-pm and linux-acpi?
> > 
> > 
> > 
> > 
> 
> Sure if it needs to spin again I'll send it to those lists as well.
> 
> Here's a lore link for you for now though if you want to respond to the 
> other patches.
> 
> https://lore.kernel.org/platform-driver-x86/0cd6648d-21f1-445d-95f6-20f580bbcfd1@amd.com/T/

Thanks, but I'm not the only person on linux-acpi and linux-pm
that may be interested in these changes.

Also please note that the material is related to ACPI and PM, so
quite relevant for those lists.

Re: [PATCH 0/4] Add support for drivers to decide bridge D3 policy

[Hans de Goede]

Hi,

On 10/25/23 04:05, Mario Limonciello wrote:
> The policy for whether PCI bridges are allowed to select D3 is dictated
> by empirical results that are enumerated into pci_bridge_d3_possible().
> 
> In Windows this behaves differently in that Windows internal policy is
> not used for devices when a power engine plugin driver provided by the
> SOC vendor is installed.  This driver is used to decide the policy in
> those cases.
> 
> This series implements a system that lets drivers register such a policy
> control as well. It isn't activated for any SOCs by default.

I must admit that I've lost track of the status of this series...

With that said patch 4/4 looks good to me and I believe that
if this series gets accepted it will be best to send 4/4
upstream together with the rest through some other tree
then the the pdx86 tree.

So here is my ack for sending a future version of patch 4/4
("platform/x86/amd: pmc: Add support for using constraints
to decide D3 policy") upstream through another subsystem tree:

Acked-by: Hans de Goede <hdegoede@redhat.com>

Regards,

Hans






> This is heavily leveraged from the work in [1]
> 
> [1] https://lore.kernel.org/platform-driver-x86/20230906184354.45846-1-mario.limonciello@amd.com/
> 
> RFC v1->PATCH v1
>  * Simplify the logic, use pci_d3cold_enable()/pci_d3cold_disable() functions
>  * Roll https://lore.kernel.org/linux-pci/20231004144731.158342-1-mario.limonciello@amd.com/ into series
>  * Updates for some typos
>  * Re-order series.  Patches 1 and 2 can potentially apply to PCI tree, 3 and 4 to platform-x86 tree.
> 
> Mario Limonciello (4):
>   PCI: Make d3cold_allowed sysfs attribute read only
>   PCI: Refresh root ports in pci_bridge_d3_update()
>   ACPI: x86: s2idle: Export symbol for fetching constraints for module
>     use
>   platform/x86/amd: pmc: Add support for using constraints to decide D3
>     policy
> 
>  Documentation/ABI/testing/sysfs-bus-pci |  4 +-
>  drivers/acpi/x86/s2idle.c               |  1 +
>  drivers/pci/pci-acpi.c                  |  2 +-
>  drivers/pci/pci-sysfs.c                 | 14 +-----
>  drivers/pci/pci.c                       | 12 ++++--
>  drivers/platform/x86/amd/pmc/pmc.c      | 57 +++++++++++++++++++++++++
>  include/linux/pci.h                     |  1 -
>  7 files changed, 72 insertions(+), 19 deletions(-)
>