From: Bjorn Helgaas <bhelgaas@google.com>
We want to disable PTM on Root Ports because that allows some chips, e.g.,
Intel mobile chips since Coffee Lake, to enter a lower-power PM state.
That means we also have to disable PTM on downstream devices. PCIe r6.0,
sec 2.2.8, recommends that functions support generation of messages in
non-D0 states, so we have to assume Switch Upstream Ports or Endpoints may
send PTM Requests while in D1, D2, and D3hot. A PTM message received by a
Downstream Port (including a Root Port) with PTM disabled must be treated
as an Unsupported Request (sec 6.21.3).
PTM was previously disabled only for Root Ports, and it was disabled in
pci_prepare_to_sleep(), which is not called at all if a driver supports
legacy PM or does its own state saving.
Instead, disable PTM early in pci_pm_suspend() and pci_pm_runtime_suspend()
so we do it in all cases.
Previously PTM was disabled *after* saving device state, so the state
restore on resume automatically re-enabled it. Since we now disable PTM
*before* saving state, we must explicitly re-enable it.
Here's a sample of errors that occur when PTM is disabled only on the Root
Port. With this topology:
0000:00:1d.0 Root Port to [bus 08-71]
0000:08:00.0 Switch Upstream Port to [bus 09-71]
Kai-Heng reported errors like this:
pcieport 0000:00:1d.0: AER: Uncorrected (Non-Fatal) error received: 0000:00:1d.0
pcieport 0000:00:1d.0: PCIe Bus Error: severity=Uncorrected (Non-Fatal), type=Transaction Layer, (Requester ID)
pcieport 0000:00:1d.0: device [8086:7ab0] error status/mask=00100000/00004000
pcieport 0000:00:1d.0: [20] UnsupReq (First)
pcieport 0000:00:1d.0: AER: TLP Header: 34000000 08000052 00000000 00000000
Decoding TLP header 0x34...... (0011 0100b) and 0x08000052:
Fmt 001b 4 DW header, no data
Type 1 0100b Msg (Local - Terminate at Receiver)
Requester ID 0x0800 Bus 08 Devfn 00.0
Message Code 0x52 0101 0010b PTM Request
The 00:1d.0 Root Port logged an Unsupported Request error when it received
a PTM Request with Requester ID 08:00.0.
Fixes: a697f072f5da ("PCI: Disable PTM during suspend to save power")
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=215453
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216210
Based-on: https://lore.kernel.org/r/20220706123244.18056-1-kai.heng.feng@canonical.com
Based-on-patch-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Reported-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
drivers/pci/pci-driver.c | 14 ++++++++++++++
drivers/pci/pci.c | 20 --------------------
2 files changed, 14 insertions(+), 20 deletions(-)
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 2815922ac525..115febaa7e0b 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -772,6 +772,12 @@ static int pci_pm_suspend(struct device *dev)
struct pci_dev *pci_dev = to_pci_dev(dev);
const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
+ /*
+ * Disabling PTM allows some systems, e.g., Intel mobile chips
+ * since Coffee Lake, to enter a lower-power PM state.
+ */
+ pci_disable_ptm(pci_dev);
+
pci_dev->skip_bus_pm = false;
if (pci_has_legacy_pm_support(pci_dev))
@@ -982,6 +988,9 @@ static int pci_pm_resume(struct device *dev)
if (pci_dev->state_saved)
pci_restore_standard_config(pci_dev);
+ if (pci_dev->ptm_enabled)
+ pci_enable_ptm(pci_dev, NULL);
+
if (pci_has_legacy_pm_support(pci_dev))
return pci_legacy_resume(dev);
@@ -1269,6 +1278,8 @@ static int pci_pm_runtime_suspend(struct device *dev)
pci_power_t prev = pci_dev->current_state;
int error;
+ pci_disable_ptm(pci_dev);
+
/*
* If pci_dev->driver is not set (unbound), we leave the device in D0,
* but it may go to D3cold when the bridge above it runtime suspends.
@@ -1331,6 +1342,9 @@ static int pci_pm_runtime_resume(struct device *dev)
*/
pci_pm_default_resume_early(pci_dev);
+ if (pci_dev->ptm_enabled)
+ pci_enable_ptm(pci_dev, NULL);
+
if (!pci_dev->driver)
return 0;
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 95bc329e74c0..b0e2968c8cca 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2706,16 +2706,6 @@ int pci_prepare_to_sleep(struct pci_dev *dev)
if (target_state == PCI_POWER_ERROR)
return -EIO;
- /*
- * There are systems (for example, Intel mobile chips since Coffee
- * Lake) where the power drawn while suspended can be significantly
- * reduced by disabling PTM on PCIe root ports as this allows the
- * port to enter a lower-power PM state and the SoC to reach a
- * lower-power idle state as a whole.
- */
- if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT)
- pci_disable_ptm(dev);
-
pci_enable_wake(dev, target_state, wakeup);
error = pci_set_power_state(dev, target_state);
@@ -2764,16 +2754,6 @@ int pci_finish_runtime_suspend(struct pci_dev *dev)
if (target_state == PCI_POWER_ERROR)
return -EIO;
- /*
- * There are systems (for example, Intel mobile chips since Coffee
- * Lake) where the power drawn while suspended can be significantly
- * reduced by disabling PTM on PCIe root ports as this allows the
- * port to enter a lower-power PM state and the SoC to reach a
- * lower-power idle state as a whole.
- */
- if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT)
- pci_disable_ptm(dev);
-
__pci_enable_wake(dev, target_state, pci_dev_run_wake(dev));
error = pci_set_power_state(dev, target_state);
--
2.25.1Hi Bjorn,
I love your patch! Yet something to improve:
[auto build test ERROR on helgaas-pci/next]
[also build test ERROR on linus/master v6.0-rc3 next-20220901]
[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/Bjorn-Helgaas/PCI-PM-Always-disable-PTM-for-all-devices-during-suspend/20220903-073808
base: https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git next
config: x86_64-randconfig-a015 (https://download.01.org/0day-ci/archive/20220903/202209031256.McjuB8mz-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.3.0-5) 11.3.0
reproduce (this is a W=1 build):
# https://github.com/intel-lab-lkp/linux/commit/809e1c954b459ee37193c4ab9fa843243fbd7fa9
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Bjorn-Helgaas/PCI-PM-Always-disable-PTM-for-all-devices-during-suspend/20220903-073808
git checkout 809e1c954b459ee37193c4ab9fa843243fbd7fa9
# save the config file
mkdir build_dir && cp config build_dir/.config
make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash
If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
drivers/pci/pci-driver.c: In function 'pci_pm_runtime_resume':
>> drivers/pci/pci-driver.c:1350:22: error: 'struct pci_dev' has no member named 'ptm_enabled'; did you mean 'ats_enabled'?
1350 | if (pci_dev->ptm_enabled)
| ^~~~~~~~~~~
| ats_enabled
vim +1350 drivers/pci/pci-driver.c
1335
1336 static int pci_pm_runtime_resume(struct device *dev)
1337 {
1338 struct pci_dev *pci_dev = to_pci_dev(dev);
1339 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
1340 pci_power_t prev_state = pci_dev->current_state;
1341 int error = 0;
1342
1343 /*
1344 * Restoring config space is necessary even if the device is not bound
1345 * to a driver because although we left it in D0, it may have gone to
1346 * D3cold when the bridge above it runtime suspended.
1347 */
1348 pci_pm_default_resume_early(pci_dev);
1349
> 1350 if (pci_dev->ptm_enabled)
1351 pci_enable_ptm(pci_dev, NULL);
1352
1353 if (!pci_dev->driver)
1354 return 0;
1355
1356 pci_fixup_device(pci_fixup_resume_early, pci_dev);
1357 pci_pm_default_resume(pci_dev);
1358
1359 if (prev_state == PCI_D3cold)
1360 pci_pm_bridge_power_up_actions(pci_dev);
1361
1362 if (pm && pm->runtime_resume)
1363 error = pm->runtime_resume(dev);
1364
1365 return error;
1366 }
1367
--
0-DAY CI Kernel Test Service
https://01.org/lkp
Hi Bjorn,
I love your patch! Yet something to improve:
[auto build test ERROR on helgaas-pci/next]
[also build test ERROR on linus/master v6.0-rc3 next-20220901]
[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/Bjorn-Helgaas/PCI-PM-Always-disable-PTM-for-all-devices-during-suspend/20220903-073808
base: https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git next
config: riscv-randconfig-r042-20220901 (https://download.01.org/0day-ci/archive/20220903/202209031120.PkNnRSt8-lkp@intel.com/config)
compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project c55b41d5199d2394dd6cdb8f52180d8b81d809d4)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install riscv cross compiling tool for clang build
# apt-get install binutils-riscv64-linux-gnu
# https://github.com/intel-lab-lkp/linux/commit/809e1c954b459ee37193c4ab9fa843243fbd7fa9
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Bjorn-Helgaas/PCI-PM-Always-disable-PTM-for-all-devices-during-suspend/20220903-073808
git checkout 809e1c954b459ee37193c4ab9fa843243fbd7fa9
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash drivers/pci/
If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
>> drivers/pci/pci-driver.c:1350:15: error: no member named 'ptm_enabled' in 'struct pci_dev'
if (pci_dev->ptm_enabled)
~~~~~~~ ^
1 error generated.
vim +1350 drivers/pci/pci-driver.c
1335
1336 static int pci_pm_runtime_resume(struct device *dev)
1337 {
1338 struct pci_dev *pci_dev = to_pci_dev(dev);
1339 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
1340 pci_power_t prev_state = pci_dev->current_state;
1341 int error = 0;
1342
1343 /*
1344 * Restoring config space is necessary even if the device is not bound
1345 * to a driver because although we left it in D0, it may have gone to
1346 * D3cold when the bridge above it runtime suspended.
1347 */
1348 pci_pm_default_resume_early(pci_dev);
1349
> 1350 if (pci_dev->ptm_enabled)
1351 pci_enable_ptm(pci_dev, NULL);
1352
1353 if (!pci_dev->driver)
1354 return 0;
1355
1356 pci_fixup_device(pci_fixup_resume_early, pci_dev);
1357 pci_pm_default_resume(pci_dev);
1358
1359 if (prev_state == PCI_D3cold)
1360 pci_pm_bridge_power_up_actions(pci_dev);
1361
1362 if (pm && pm->runtime_resume)
1363 error = pm->runtime_resume(dev);
1364
1365 return error;
1366 }
1367
--
0-DAY CI Kernel Test Service
https://01.org/lkp
On 9/2/22 4:35 PM, Bjorn Helgaas wrote:
> From: Bjorn Helgaas <bhelgaas@google.com>
>
> We want to disable PTM on Root Ports because that allows some chips, e.g.,
> Intel mobile chips since Coffee Lake, to enter a lower-power PM state.
>
> That means we also have to disable PTM on downstream devices. PCIe r6.0,
> sec 2.2.8, recommends that functions support generation of messages in
> non-D0 states, so we have to assume Switch Upstream Ports or Endpoints may
> send PTM Requests while in D1, D2, and D3hot. A PTM message received by a
> Downstream Port (including a Root Port) with PTM disabled must be treated
> as an Unsupported Request (sec 6.21.3).
>
> PTM was previously disabled only for Root Ports, and it was disabled in
> pci_prepare_to_sleep(), which is not called at all if a driver supports
> legacy PM or does its own state saving.
>
> Instead, disable PTM early in pci_pm_suspend() and pci_pm_runtime_suspend()
> so we do it in all cases.
>
> Previously PTM was disabled *after* saving device state, so the state
> restore on resume automatically re-enabled it. Since we now disable PTM
> *before* saving state, we must explicitly re-enable it.
>
> Here's a sample of errors that occur when PTM is disabled only on the Root
> Port. With this topology:
>
> 0000:00:1d.0 Root Port to [bus 08-71]
> 0000:08:00.0 Switch Upstream Port to [bus 09-71]
>
> Kai-Heng reported errors like this:
>
> pcieport 0000:00:1d.0: AER: Uncorrected (Non-Fatal) error received: 0000:00:1d.0
> pcieport 0000:00:1d.0: PCIe Bus Error: severity=Uncorrected (Non-Fatal), type=Transaction Layer, (Requester ID)
> pcieport 0000:00:1d.0: device [8086:7ab0] error status/mask=00100000/00004000
> pcieport 0000:00:1d.0: [20] UnsupReq (First)
> pcieport 0000:00:1d.0: AER: TLP Header: 34000000 08000052 00000000 00000000
>
> Decoding TLP header 0x34...... (0011 0100b) and 0x08000052:
>
> Fmt 001b 4 DW header, no data
> Type 1 0100b Msg (Local - Terminate at Receiver)
> Requester ID 0x0800 Bus 08 Devfn 00.0
> Message Code 0x52 0101 0010b PTM Request
>
> The 00:1d.0 Root Port logged an Unsupported Request error when it received
> a PTM Request with Requester ID 08:00.0.
>
> Fixes: a697f072f5da ("PCI: Disable PTM during suspend to save power")
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=215453
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216210
> Based-on: https://lore.kernel.org/r/20220706123244.18056-1-kai.heng.feng@canonical.com
> Based-on-patch-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> Reported-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
> ---
> drivers/pci/pci-driver.c | 14 ++++++++++++++
> drivers/pci/pci.c | 20 --------------------
> 2 files changed, 14 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
> index 2815922ac525..115febaa7e0b 100644
> --- a/drivers/pci/pci-driver.c
> +++ b/drivers/pci/pci-driver.c
> @@ -772,6 +772,12 @@ static int pci_pm_suspend(struct device *dev)
> struct pci_dev *pci_dev = to_pci_dev(dev);
> const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
>
> + /*
> + * Disabling PTM allows some systems, e.g., Intel mobile chips
> + * since Coffee Lake, to enter a lower-power PM state.
> + */
> + pci_disable_ptm(pci_dev);
I think you can use "if (pci_dev->ptm_enabled)" check for pci_disable_ptm()
as well. This will avoid unnecessary checks in pci_disable_ptm().
> +
> pci_dev->skip_bus_pm = false;
>
> if (pci_has_legacy_pm_support(pci_dev))
> @@ -982,6 +988,9 @@ static int pci_pm_resume(struct device *dev)
> if (pci_dev->state_saved)
> pci_restore_standard_config(pci_dev);
>
> + if (pci_dev->ptm_enabled)
> + pci_enable_ptm(pci_dev, NULL);
> +
> if (pci_has_legacy_pm_support(pci_dev))
> return pci_legacy_resume(dev);
>
> @@ -1269,6 +1278,8 @@ static int pci_pm_runtime_suspend(struct device *dev)
> pci_power_t prev = pci_dev->current_state;
> int error;
>
> + pci_disable_ptm(pci_dev);
> +
> /*
> * If pci_dev->driver is not set (unbound), we leave the device in D0,
> * but it may go to D3cold when the bridge above it runtime suspends.
> @@ -1331,6 +1342,9 @@ static int pci_pm_runtime_resume(struct device *dev)
> */
> pci_pm_default_resume_early(pci_dev);
>
> + if (pci_dev->ptm_enabled)
> + pci_enable_ptm(pci_dev, NULL);
> +
> if (!pci_dev->driver)
> return 0;
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 95bc329e74c0..b0e2968c8cca 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -2706,16 +2706,6 @@ int pci_prepare_to_sleep(struct pci_dev *dev)
> if (target_state == PCI_POWER_ERROR)
> return -EIO;
>
> - /*
> - * There are systems (for example, Intel mobile chips since Coffee
> - * Lake) where the power drawn while suspended can be significantly
> - * reduced by disabling PTM on PCIe root ports as this allows the
> - * port to enter a lower-power PM state and the SoC to reach a
> - * lower-power idle state as a whole.
> - */
> - if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT)
> - pci_disable_ptm(dev);
> -
> pci_enable_wake(dev, target_state, wakeup);
>
> error = pci_set_power_state(dev, target_state);
> @@ -2764,16 +2754,6 @@ int pci_finish_runtime_suspend(struct pci_dev *dev)
> if (target_state == PCI_POWER_ERROR)
> return -EIO;
>
> - /*
> - * There are systems (for example, Intel mobile chips since Coffee
> - * Lake) where the power drawn while suspended can be significantly
> - * reduced by disabling PTM on PCIe root ports as this allows the
> - * port to enter a lower-power PM state and the SoC to reach a
> - * lower-power idle state as a whole.
> - */
> - if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT)
> - pci_disable_ptm(dev);
> -
> __pci_enable_wake(dev, target_state, pci_dev_run_wake(dev));
>
> error = pci_set_power_state(dev, target_state);
--
Sathyanarayanan Kuppuswamy
Linux Kernel Developer
On Sat, Sep 3, 2022 at 1:59 AM Sathyanarayanan Kuppuswamy
<sathyanarayanan.kuppuswamy@linux.intel.com> wrote:
>
>
>
> On 9/2/22 4:35 PM, Bjorn Helgaas wrote:
> > From: Bjorn Helgaas <bhelgaas@google.com>
> >
> > We want to disable PTM on Root Ports because that allows some chips, e.g.,
> > Intel mobile chips since Coffee Lake, to enter a lower-power PM state.
> >
> > That means we also have to disable PTM on downstream devices. PCIe r6.0,
> > sec 2.2.8, recommends that functions support generation of messages in
> > non-D0 states, so we have to assume Switch Upstream Ports or Endpoints may
> > send PTM Requests while in D1, D2, and D3hot. A PTM message received by a
> > Downstream Port (including a Root Port) with PTM disabled must be treated
> > as an Unsupported Request (sec 6.21.3).
> >
> > PTM was previously disabled only for Root Ports, and it was disabled in
> > pci_prepare_to_sleep(), which is not called at all if a driver supports
> > legacy PM or does its own state saving.
> >
> > Instead, disable PTM early in pci_pm_suspend() and pci_pm_runtime_suspend()
> > so we do it in all cases.
> >
> > Previously PTM was disabled *after* saving device state, so the state
> > restore on resume automatically re-enabled it. Since we now disable PTM
> > *before* saving state, we must explicitly re-enable it.
> >
> > Here's a sample of errors that occur when PTM is disabled only on the Root
> > Port. With this topology:
> >
> > 0000:00:1d.0 Root Port to [bus 08-71]
> > 0000:08:00.0 Switch Upstream Port to [bus 09-71]
> >
> > Kai-Heng reported errors like this:
> >
> > pcieport 0000:00:1d.0: AER: Uncorrected (Non-Fatal) error received: 0000:00:1d.0
> > pcieport 0000:00:1d.0: PCIe Bus Error: severity=Uncorrected (Non-Fatal), type=Transaction Layer, (Requester ID)
> > pcieport 0000:00:1d.0: device [8086:7ab0] error status/mask=00100000/00004000
> > pcieport 0000:00:1d.0: [20] UnsupReq (First)
> > pcieport 0000:00:1d.0: AER: TLP Header: 34000000 08000052 00000000 00000000
> >
> > Decoding TLP header 0x34...... (0011 0100b) and 0x08000052:
> >
> > Fmt 001b 4 DW header, no data
> > Type 1 0100b Msg (Local - Terminate at Receiver)
> > Requester ID 0x0800 Bus 08 Devfn 00.0
> > Message Code 0x52 0101 0010b PTM Request
> >
> > The 00:1d.0 Root Port logged an Unsupported Request error when it received
> > a PTM Request with Requester ID 08:00.0.
> >
> > Fixes: a697f072f5da ("PCI: Disable PTM during suspend to save power")
> > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=215453
> > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216210
> > Based-on: https://lore.kernel.org/r/20220706123244.18056-1-kai.heng.feng@canonical.com
> > Based-on-patch-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> > Reported-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> > Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
> > ---
> > drivers/pci/pci-driver.c | 14 ++++++++++++++
> > drivers/pci/pci.c | 20 --------------------
> > 2 files changed, 14 insertions(+), 20 deletions(-)
> >
> > diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
> > index 2815922ac525..115febaa7e0b 100644
> > --- a/drivers/pci/pci-driver.c
> > +++ b/drivers/pci/pci-driver.c
> > @@ -772,6 +772,12 @@ static int pci_pm_suspend(struct device *dev)
> > struct pci_dev *pci_dev = to_pci_dev(dev);
> > const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
> >
> > + /*
> > + * Disabling PTM allows some systems, e.g., Intel mobile chips
> > + * since Coffee Lake, to enter a lower-power PM state.
> > + */
> > + pci_disable_ptm(pci_dev);
>
> I think you can use "if (pci_dev->ptm_enabled)" check for pci_disable_ptm()
> as well. This will avoid unnecessary checks in pci_disable_ptm().
Or use that check in pci_disable_ptm() instead of the pci_is_pcie() one.
Also, I would remae pci_disable_ptm() to pci_suspend_ptm() (because
its role is to temporarily disable PTM for system-wide suspend) and
introduc pci_resume_ptm() that will do
if (pci_dev->ptm_enabled)
pci_enable_ptm(pci_dev, NULL);
> > +
> > pci_dev->skip_bus_pm = false;
> >
> > if (pci_has_legacy_pm_support(pci_dev))
> > @@ -982,6 +988,9 @@ static int pci_pm_resume(struct device *dev)
> > if (pci_dev->state_saved)
> > pci_restore_standard_config(pci_dev);
> >
> > + if (pci_dev->ptm_enabled)
> > + pci_enable_ptm(pci_dev, NULL);
> > +
> > if (pci_has_legacy_pm_support(pci_dev))
> > return pci_legacy_resume(dev);
> >
> > @@ -1269,6 +1278,8 @@ static int pci_pm_runtime_suspend(struct device *dev)
> > pci_power_t prev = pci_dev->current_state;
> > int error;
> >
> > + pci_disable_ptm(pci_dev);
> > +
> > /*
> > * If pci_dev->driver is not set (unbound), we leave the device in D0,
> > * but it may go to D3cold when the bridge above it runtime suspends.
> > @@ -1331,6 +1342,9 @@ static int pci_pm_runtime_resume(struct device *dev)
> > */
> > pci_pm_default_resume_early(pci_dev);
> >
> > + if (pci_dev->ptm_enabled)
> > + pci_enable_ptm(pci_dev, NULL);
> > +
> > if (!pci_dev->driver)
> > return 0;
> >
> > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> > index 95bc329e74c0..b0e2968c8cca 100644
> > --- a/drivers/pci/pci.c
> > +++ b/drivers/pci/pci.c
> > @@ -2706,16 +2706,6 @@ int pci_prepare_to_sleep(struct pci_dev *dev)
> > if (target_state == PCI_POWER_ERROR)
> > return -EIO;
> >
> > - /*
> > - * There are systems (for example, Intel mobile chips since Coffee
> > - * Lake) where the power drawn while suspended can be significantly
> > - * reduced by disabling PTM on PCIe root ports as this allows the
> > - * port to enter a lower-power PM state and the SoC to reach a
> > - * lower-power idle state as a whole.
> > - */
> > - if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT)
> > - pci_disable_ptm(dev);
> > -
> > pci_enable_wake(dev, target_state, wakeup);
> >
> > error = pci_set_power_state(dev, target_state);
> > @@ -2764,16 +2754,6 @@ int pci_finish_runtime_suspend(struct pci_dev *dev)
> > if (target_state == PCI_POWER_ERROR)
> > return -EIO;
> >
> > - /*
> > - * There are systems (for example, Intel mobile chips since Coffee
> > - * Lake) where the power drawn while suspended can be significantly
> > - * reduced by disabling PTM on PCIe root ports as this allows the
> > - * port to enter a lower-power PM state and the SoC to reach a
> > - * lower-power idle state as a whole.
> > - */
> > - if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT)
> > - pci_disable_ptm(dev);
> > -
> > __pci_enable_wake(dev, target_state, pci_dev_run_wake(dev));
> >
> > error = pci_set_power_state(dev, target_state);
>
> --
> Sathyanarayanan Kuppuswamy
> Linux Kernel Developer
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