diff mbox series

[v2,3/3] PCI/PM: Always disable PTM for all devices during suspend

Message ID 20220902233543.390890-4-helgaas@kernel.org (mailing list archive)
State Superseded
Headers show
Series PCI/PM: Always disable PTM for all devices during suspend | expand

Commit Message

Bjorn Helgaas Sept. 2, 2022, 11:35 p.m. UTC 
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(-)

Comments

Kuppuswamy Sathyanarayanan Sept. 2, 2022, 11:59 p.m. UTC | #1 
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);
kernel test robot Sept. 3, 2022, 4:07 a.m. UTC | #2 
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
kernel test robot Sept. 3, 2022, 4:18 a.m. UTC | #3 
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: 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
Rafael J. Wysocki Sept. 3, 2022, 5:13 p.m. UTC | #4 
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
diff mbox series

Patch

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);