diff mbox series

[v10,7/7] PCI: Use device constraints to decide PCI target state fallback policy

Message ID 20230804210129.5356-8-mario.limonciello@amd.com
State New
Headers show
Series Fix wakeup problems on some AMD platforms | expand

Commit Message

Mario Limonciello Aug. 4, 2023, 9:01 p.m. UTC
Since commit 9d26d3a8f1b0 ("PCI: Put PCIe ports into D3 during suspend")
PCIe ports from modern machines (>=2015) are allowed to be put into D3 by
storing a value to the `bridge_d3` variable in the `struct pci_dev`
structure.

pci_power_manageable() uses this variable to indicate a PCIe port can
enter D3.
pci_pm_suspend_noirq() uses the return from pci_power_manageable() to
decide whether to try to put a device into its target state for a sleep
cycle via pci_prepare_to_sleep().

For devices that support D3, the target state is selected by this policy:
1. If platform_pci_power_manageable():
   Use platform_pci_choose_state()
2. If the device is armed for wakeup:
   Select the deepest D-state that supports a PME.
3. Else:
   Use D3hot.

Devices are considered power manageable by the platform when they have
one or more objects described in the table in section 7.3 of the ACPI 6.5
specification.

When devices are not considered power manageable; specs are ambiguous as
to what should happen.  In this situation Windows 11 leaves PCIe
ports in D0 while Linux puts them into D3 due to the above mentioned
commit.

In Windows systems that support Modern Standby specify hardware
pre-conditions for the SoC to achieve the lowest power state by device
constraints in a SOC specific "Power Engine Plugin" (PEP) [2] [3].
They can be marked as disabled or enabled and when enabled can specify
the minimum power state required for an ACPI device.

When it is ambiguous what should happen, adjust the logic for
pci_target_state() to check whether a device constraint is present
and enabled.
* If power manageable by ACPI use this to get to select target state
* If a device constraint is present but disabled then choose D0
* If a device constraint is present and enabled then use it
* If a device constraint is not present, then continue to existing
logic (if marked for wakeup use deepest state that PME works)
* If not marked for wakeup choose D3hot

Link: https://uefi.org/specs/ACPI/6.5/07_Power_and_Performance_Mgmt.html#device-power-management-objects [1]
Link: https://learn.microsoft.com/en-us/windows-hardware/design/device-experiences/platform-design-for-modern-standby#low-power-core-silicon-cpu-soc-dram [2]
Link: https://uefi.org/sites/default/files/resources/Intel_ACPI_Low_Power_S0_Idle.pdf [3]
Fixes: 9d26d3a8f1b0 ("PCI: Put PCIe ports into D3 during suspend")
Reported-by: Iain Lane <iain@orangesquash.org.uk>
Closes: https://forums.lenovo.com/t5/Ubuntu/Z13-can-t-resume-from-suspend-with-external-USB-keyboard/m-p/5217121
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
v9->v10:
 * kerneldoc fixes
 * split into more patches
 * adjust return variable handling
 * Adjust call-site to avoid problems for devices already in d3cold
---
 drivers/pci/pci.c | 47 ++++++++++++++++++++++++++++++++++-------------
 1 file changed, 34 insertions(+), 13 deletions(-)

Comments

kernel test robot Aug. 5, 2023, 5:22 a.m. UTC | #1
Hi Mario,

kernel test robot noticed the following build errors:

[auto build test ERROR on rafael-pm/linux-next]
[also build test ERROR on pci/next pci/for-linus westeri-thunderbolt/next linus/master v6.5-rc4 next-20230804]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Mario-Limonciello/ACPI-Add-comments-to-clarify-some-ifdef-statements/20230805-050559
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
patch link:    https://lore.kernel.org/r/20230804210129.5356-8-mario.limonciello%40amd.com
patch subject: [PATCH v10 7/7] PCI: Use device constraints to decide PCI target state fallback policy
config: mips-randconfig-r032-20230731 (https://download.01.org/0day-ci/archive/20230805/202308051340.k7mCXXL3-lkp@intel.com/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a)
reproduce: (https://download.01.org/0day-ci/archive/20230805/202308051340.k7mCXXL3-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202308051340.k7mCXXL3-lkp@intel.com/

All errors (new ones prefixed by >>):

>> drivers/pci/pci.c:1090:9: error: call to undeclared function 'acpi_get_lps0_constraint'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    1090 |         return acpi_get_lps0_constraint(&dev->dev);
         |                ^
   1 error generated.


vim +/acpi_get_lps0_constraint +1090 drivers/pci/pci.c

  1084	
  1085	static inline int platform_get_constraint(struct pci_dev *dev)
  1086	{
  1087		if (pci_use_mid_pm())
  1088			return -ENODEV;
  1089	
> 1090		return acpi_get_lps0_constraint(&dev->dev);
  1091	}
  1092
kernel test robot Aug. 5, 2023, 10:27 a.m. UTC | #2
Hi Mario,

kernel test robot noticed the following build warnings:

[auto build test WARNING on rafael-pm/linux-next]
[also build test WARNING on pci/next pci/for-linus westeri-thunderbolt/next linus/master v6.5-rc4 next-20230804]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Mario-Limonciello/ACPI-Add-comments-to-clarify-some-ifdef-statements/20230805-050559
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
patch link:    https://lore.kernel.org/r/20230804210129.5356-8-mario.limonciello%40amd.com
patch subject: [PATCH v10 7/7] PCI: Use device constraints to decide PCI target state fallback policy
config: x86_64-randconfig-r072-20230730 (https://download.01.org/0day-ci/archive/20230805/202308051831.tHlat46E-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce: (https://download.01.org/0day-ci/archive/20230805/202308051831.tHlat46E-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202308051831.tHlat46E-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
   drivers/pci/pci.c:1117:36: sparse: sparse: incorrect type in assignment (different base types) @@     expected restricted pci_power_t [usertype] current_state @@     got int @@
   drivers/pci/pci.c:1117:36: sparse:     expected restricted pci_power_t [usertype] current_state
   drivers/pci/pci.c:1117:36: sparse:     got int
   drivers/pci/pci.c:1267:15: sparse: sparse: incorrect type in assignment (different base types) @@     expected restricted pci_power_t [assigned] [usertype] state @@     got int @@
   drivers/pci/pci.c:1267:15: sparse:     expected restricted pci_power_t [assigned] [usertype] state
   drivers/pci/pci.c:1267:15: sparse:     got int
   drivers/pci/pci.c:1269:50: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/pci/pci.c:1269:69: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/pci/pci.c:1317:28: sparse: sparse: incorrect type in assignment (different base types) @@     expected restricted pci_power_t [usertype] current_state @@     got int @@
   drivers/pci/pci.c:1317:28: sparse:     expected restricted pci_power_t [usertype] current_state
   drivers/pci/pci.c:1317:28: sparse:     got int
   drivers/pci/pci.c:1392:16: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/pci/pci.c:1392:35: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/pci/pci.c:1392:52: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/pci/pci.c:1392:70: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/pci/pci.c:1414:15: sparse: sparse: invalid assignment: |=
   drivers/pci/pci.c:1414:15: sparse:    left side has type unsigned short
   drivers/pci/pci.c:1414:15: sparse:    right side has type restricted pci_power_t
   drivers/pci/pci.c:1426:28: sparse: sparse: incorrect type in assignment (different base types) @@     expected restricted pci_power_t [usertype] current_state @@     got int @@
   drivers/pci/pci.c:1426:28: sparse:     expected restricted pci_power_t [usertype] current_state
   drivers/pci/pci.c:1426:28: sparse:     got int
   drivers/pci/pci.c:1457:13: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/pci/pci.c:1457:21: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/pci/pci.c:1459:18: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/pci/pci.c:1459:26: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/pci/pci.c:1482:13: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/pci/pci.c:1482:22: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/pci/pci.c:1840:38: sparse: sparse: array of flexible structures
   drivers/pci/pci.c:2416:44: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/pci/pci.c:2679:52: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/pci/pci.c:2680:22: sparse: sparse: restricted pci_power_t degrades to integer
>> drivers/pci/pci.c:2729:20: sparse: sparse: incorrect type in assignment (different base types) @@     expected restricted pci_power_t [usertype] constraint @@     got int @@
   drivers/pci/pci.c:2729:20: sparse:     expected restricted pci_power_t [usertype] constraint
   drivers/pci/pci.c:2729:20: sparse:     got int
   drivers/pci/pci.c:2730:13: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/pci/pci.c:2737:21: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/pci/pci.c:2737:33: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/pci/pci.c:2904:20: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/pci/pci.c:2904:38: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/pci/pci.c:2927:49: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/pci/pci.c:2927:67: sparse: sparse: restricted pci_power_t degrades to integer
   drivers/pci/pci.c:4894:13: sparse: sparse: invalid assignment: |=
   drivers/pci/pci.c:4894:13: sparse:    left side has type unsigned short
   drivers/pci/pci.c:4894:13: sparse:    right side has type restricted pci_power_t
   drivers/pci/pci.c:4899:13: sparse: sparse: invalid assignment: |=
   drivers/pci/pci.c:4899:13: sparse:    left side has type unsigned short
   drivers/pci/pci.c:4899:13: sparse:    right side has type restricted pci_power_t
   drivers/pci/pci.c:1064:24: sparse: sparse: incorrect type in return expression (different base types) @@     expected int @@     got restricted pci_power_t [usertype] @@
   drivers/pci/pci.c:1064:24: sparse:     expected int
   drivers/pci/pci.c:1064:24: sparse:     got restricted pci_power_t [usertype]
   drivers/pci/pci.c:1064:24: sparse: sparse: incorrect type in return expression (different base types) @@     expected int @@     got restricted pci_power_t [usertype] @@
   drivers/pci/pci.c:1064:24: sparse:     expected int
   drivers/pci/pci.c:1064:24: sparse:     got restricted pci_power_t [usertype]

vim +2729 drivers/pci/pci.c

  2684	
  2685	/**
  2686	 * pci_target_state - find an appropriate low power state for a given PCI dev
  2687	 * @dev: PCI device
  2688	 * @wakeup: Whether or not wakeup functionality will be enabled for the device.
  2689	 *
  2690	 * Use underlying platform code to find a supported low power state for @dev.
  2691	 * If the platform can't manage @dev, return the deepest state from which it
  2692	 * can generate wake events, based on any available PME info.
  2693	 */
  2694	static pci_power_t pci_target_state(struct pci_dev *dev, bool wakeup)
  2695	{
  2696		pci_power_t constraint;
  2697	
  2698		if (platform_pci_power_manageable(dev)) {
  2699			/*
  2700			 * Call the platform to find the target state for the device.
  2701			 */
  2702			pci_power_t state = platform_pci_choose_state(dev);
  2703	
  2704			switch (state) {
  2705			case PCI_POWER_ERROR:
  2706			case PCI_UNKNOWN:
  2707				return PCI_D3hot;
  2708	
  2709			case PCI_D1:
  2710			case PCI_D2:
  2711				if (pci_no_d1d2(dev))
  2712					return PCI_D3hot;
  2713			}
  2714	
  2715			return state;
  2716		}
  2717	
  2718		/*
  2719		 * If the device is in D3cold even though it's not power-manageable by
  2720		 * the platform, it may have been powered down by non-standard means.
  2721		 * Best to let it slumber.
  2722		 */
  2723		if (dev->current_state == PCI_D3cold)
  2724			return PCI_D3cold;
  2725		else if (!dev->pm_cap)
  2726			return PCI_D0;
  2727	
  2728		/* if platform indicates preferred state device constraint, use it */
> 2729		constraint = platform_get_constraint(dev);
  2730		if (constraint < 0)
  2731			constraint = PCI_D3hot;
  2732	
  2733		if (wakeup && dev->pme_support) {
  2734			pci_power_t pme_state = pci_get_wake_pme_state(dev);
  2735	
  2736			/* pick the lesser of any specified constraints */
  2737			if (pme_state < constraint)
  2738				constraint = pme_state;
  2739		}
  2740	
  2741		return constraint;
  2742	}
  2743
kernel test robot Aug. 5, 2023, 10:27 a.m. UTC | #3
Hi Mario,

kernel test robot noticed the following build errors:

[auto build test ERROR on rafael-pm/linux-next]
[also build test ERROR on pci/next pci/for-linus westeri-thunderbolt/next linus/master v6.5-rc4 next-20230804]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Mario-Limonciello/ACPI-Add-comments-to-clarify-some-ifdef-statements/20230805-050559
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
patch link:    https://lore.kernel.org/r/20230804210129.5356-8-mario.limonciello%40amd.com
patch subject: [PATCH v10 7/7] PCI: Use device constraints to decide PCI target state fallback policy
config: x86_64-randconfig-r013-20230731 (https://download.01.org/0day-ci/archive/20230805/202308051803.x00umDzn-lkp@intel.com/config)
compiler: clang version 16.0.4 (https://github.com/llvm/llvm-project.git ae42196bc493ffe877a7e3dff8be32035dea4d07)
reproduce: (https://download.01.org/0day-ci/archive/20230805/202308051803.x00umDzn-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202308051803.x00umDzn-lkp@intel.com/

All errors (new ones prefixed by >>):

>> ld.lld: error: undefined symbol: acpi_get_lps0_constraint
   >>> referenced by pci.c:1090 (drivers/pci/pci.c:1090)
   >>>               vmlinux.o:(pci_target_state)
diff mbox series

Patch

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 60230da957e0c..108eacc4f8dd9 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1082,6 +1082,14 @@  static inline bool platform_pci_bridge_d3(struct pci_dev *dev)
 	return acpi_pci_bridge_d3(dev);
 }
 
+static inline int platform_get_constraint(struct pci_dev *dev)
+{
+	if (pci_use_mid_pm())
+		return -ENODEV;
+
+	return acpi_get_lps0_constraint(&dev->dev);
+}
+
 /**
  * pci_update_current_state - Read power state of given device and cache it
  * @dev: PCI device to handle.
@@ -2660,6 +2668,20 @@  int pci_wake_from_d3(struct pci_dev *dev, bool enable)
 }
 EXPORT_SYMBOL(pci_wake_from_d3);
 
+/*
+ * Find the deepest state from which the device can generate
+ * PME#.
+ */
+static pci_power_t pci_get_wake_pme_state(struct pci_dev *dev)
+{
+	pci_power_t state = PCI_D3hot;
+
+	while (state && !(dev->pme_support & (1 << state)))
+		state--;
+
+	return state;
+}
+
 /**
  * pci_target_state - find an appropriate low power state for a given PCI dev
  * @dev: PCI device
@@ -2671,6 +2693,8 @@  EXPORT_SYMBOL(pci_wake_from_d3);
  */
 static pci_power_t pci_target_state(struct pci_dev *dev, bool wakeup)
 {
+	pci_power_t constraint;
+
 	if (platform_pci_power_manageable(dev)) {
 		/*
 		 * Call the platform to find the target state for the device.
@@ -2701,23 +2725,20 @@  static pci_power_t pci_target_state(struct pci_dev *dev, bool wakeup)
 	else if (!dev->pm_cap)
 		return PCI_D0;
 
-	if (wakeup && dev->pme_support) {
-		pci_power_t state = PCI_D3hot;
+	/* if platform indicates preferred state device constraint, use it */
+	constraint = platform_get_constraint(dev);
+	if (constraint < 0)
+		constraint = PCI_D3hot;
 
-		/*
-		 * Find the deepest state from which the device can generate
-		 * PME#.
-		 */
-		while (state && !(dev->pme_support & (1 << state)))
-			state--;
+	if (wakeup && dev->pme_support) {
+		pci_power_t pme_state = pci_get_wake_pme_state(dev);
 
-		if (state)
-			return state;
-		else if (dev->pme_support & 1)
-			return PCI_D0;
+		/* pick the lesser of any specified constraints */
+		if (pme_state < constraint)
+			constraint = pme_state;
 	}
 
-	return PCI_D3hot;
+	return constraint;
 }
 
 /**