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[1/2] vga_switcheroo: add power support for windows 10 machines.

Message ID 1457504045-12738-1-git-send-email-airlied@gmail.com (mailing list archive)
State Not Applicable, archived
Headers show

Commit Message

Dave Airlie March 9, 2016, 6:14 a.m. UTC
From: Dave Airlie <airlied@redhat.com>

Windows 10 seems to have standardised power control for the
optimus/powerxpress laptops using PR3 power resource hooks.

I'm not sure this is definitely the correct place to be
doing this, but it works for me here.

The ACPI device for the GPU I have is \_SB_.PCI0.PEG_.VID_
but the power resource hooks are on \_SB_.PCI0.PEG_, so
this patch creates a new power domain to turn the GPU
device parent off using standard ACPI calls.

Signed-off-by: Dave Airlie <airlied@redhat.com>
---
 drivers/gpu/vga/vga_switcheroo.c | 54 +++++++++++++++++++++++++++++++++++++++-
 include/linux/vga_switcheroo.h   |  3 ++-
 2 files changed, 55 insertions(+), 2 deletions(-)

Comments

Rafael J. Wysocki March 9, 2016, 1:19 p.m. UTC | #1
On Wed, Mar 9, 2016 at 7:14 AM, Dave Airlie <airlied@gmail.com> wrote:
> From: Dave Airlie <airlied@redhat.com>
>
> Windows 10 seems to have standardised power control for the
> optimus/powerxpress laptops using PR3 power resource hooks.
>
> I'm not sure this is definitely the correct place to be
> doing this, but it works for me here.
>
> The ACPI device for the GPU I have is \_SB_.PCI0.PEG_.VID_
> but the power resource hooks are on \_SB_.PCI0.PEG_, so
> this patch creates a new power domain to turn the GPU
> device parent off using standard ACPI calls.
>
> Signed-off-by: Dave Airlie <airlied@redhat.com>
> ---
>  drivers/gpu/vga/vga_switcheroo.c | 54 +++++++++++++++++++++++++++++++++++++++-
>  include/linux/vga_switcheroo.h   |  3 ++-
>  2 files changed, 55 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
> index 665ab9f..be32cb2 100644
> --- a/drivers/gpu/vga/vga_switcheroo.c
> +++ b/drivers/gpu/vga/vga_switcheroo.c
> @@ -42,7 +42,7 @@
>  #include <linux/uaccess.h>
>  #include <linux/vgaarb.h>
>  #include <linux/vga_switcheroo.h>
> -
> +#include <linux/acpi.h>
>  /**
>   * DOC: Overview
>   *
> @@ -997,3 +997,55 @@ vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device *dev,
>         return -EINVAL;
>  }
>  EXPORT_SYMBOL(vga_switcheroo_init_domain_pm_optimus_hdmi_audio);
> +
> +/* With Windows 10 the runtime suspend/resume can use power
> +   resources on the parent device */
> +static int vga_acpi_switcheroo_runtime_suspend(struct device *dev)
> +{
> +       struct pci_dev *pdev = to_pci_dev(dev);
> +       int ret;
> +       struct acpi_device *adev;
> +
> +       ret = dev->bus->pm->runtime_suspend(dev);
> +       if (ret)
> +               return ret;
> +
> +       ret = acpi_bus_get_device(ACPI_HANDLE(&pdev->dev), &adev);

You can use ACPI_COMPANION(&pdev->dev) for that.

> +       if (!ret)
> +               acpi_device_set_power(adev->parent, ACPI_STATE_D3_COLD);

Won't that mess up with the PM of the parent?  Or do we know that the
parent won't do its own PM?

> +       return 0;
> +}
> +
> +static int vga_acpi_switcheroo_runtime_resume(struct device *dev)
> +{
> +       struct pci_dev *pdev = to_pci_dev(dev);
> +       struct acpi_device *adev;
> +       int ret;
> +
> +       ret = acpi_bus_get_device(ACPI_HANDLE(&pdev->dev), &adev);

ACPI_COMPANION(&pdev->dev) here too?

> +       if (!ret)
> +               acpi_device_set_power(adev->parent, ACPI_STATE_D0);
> +       ret = dev->bus->pm->runtime_resume(dev);
> +       if (ret)
> +               return ret;
> +
> +       return 0;
> +}
> +
> +int vga_switcheroo_init_parent_pr3_ops(struct device *dev,
> +                                      struct dev_pm_domain *domain)
> +
> +{
> +       /* copy over all the bus versions */
> +       if (dev->bus && dev->bus->pm) {
> +               domain->ops = *dev->bus->pm;
> +               domain->ops.runtime_suspend = vga_acpi_switcheroo_runtime_suspend;
> +               domain->ops.runtime_resume = vga_acpi_switcheroo_runtime_resume;
> +
> +               dev_pm_domain_set(dev, domain);
> +               return 0;
> +       }
> +       dev_pm_domain_set(dev, NULL);
> +       return -EINVAL;
> +}
> +EXPORT_SYMBOL(vga_switcheroo_init_parent_pr3_ops);
> diff --git a/include/linux/vga_switcheroo.h b/include/linux/vga_switcheroo.h
> index 69e1d4a1..5ce0cbe 100644
> --- a/include/linux/vga_switcheroo.h
> +++ b/include/linux/vga_switcheroo.h
> @@ -144,6 +144,7 @@ void vga_switcheroo_set_dynamic_switch(struct pci_dev *pdev, enum vga_switcheroo
>  int vga_switcheroo_init_domain_pm_ops(struct device *dev, struct dev_pm_domain *domain);
>  void vga_switcheroo_fini_domain_pm_ops(struct device *dev);
>  int vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device *dev, struct dev_pm_domain *domain);
> +int vga_switcheroo_init_parent_pr3_ops(struct device *dev, struct dev_pm_domain *domain);
>  #else
>
>  static inline void vga_switcheroo_unregister_client(struct pci_dev *dev) {}
> @@ -163,6 +164,6 @@ static inline void vga_switcheroo_set_dynamic_switch(struct pci_dev *pdev, enum
>  static inline int vga_switcheroo_init_domain_pm_ops(struct device *dev, struct dev_pm_domain *domain) { return -EINVAL; }
>  static inline void vga_switcheroo_fini_domain_pm_ops(struct device *dev) {}
>  static inline int vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device *dev, struct dev_pm_domain *domain) { return -EINVAL; }
> -
> +static inline int vga_switcheroo_init_parent_pr3_ops(struct device *dev, struct dev_pm_domain *domain) { return -EINVAL; }
>  #endif
>  #endif /* _LINUX_VGA_SWITCHEROO_H_ */
> --
> 2.5.0
>
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Lukas Wunner March 9, 2016, 2:33 p.m. UTC | #2
Hi Dave,

On Wed, Mar 09, 2016 at 04:14:04PM +1000, Dave Airlie wrote:
> From: Dave Airlie <airlied@redhat.com>
> 
> Windows 10 seems to have standardised power control for the
> optimus/powerxpress laptops using PR3 power resource hooks.

What happened to the Optimus DSM, does this still work? If not,
echoing OFF to the vgaswitcheroo sysfs file won't power down the
GPU now, right? (If runtime pm is disabled in nouveau.)

> I'm not sure this is definitely the correct place to be
> doing this, but it works for me here.

How about implementing an additional vga_switcheroo handler somewhere
in drivers/acpi/, which looks for the PR3 hooks and registers with
vga_switcheroo if found. The ->power_state callback of that handler
would then invoke acpi_device_set_power().

The ACPI bus is scanned in the subsys_initcall section, much earlier
than nouveau is loaded (in the device_initcall section). So the ACPI
vga_switcheroo handler could register before the nouveau DSM handler
and therefore would always have a higher precedence.

In any case this patch should be amended with kerneldoc for
vga_switcheroo_init_parent_pr3_ops(), I've spent considerable time
last year to document everything and kindly ask that this water not
be muddied again. ;-)

One small nit, the headers are sorted alphabetically yet acpi.h is
added at the end.

Thanks,

Lukas

> 
> The ACPI device for the GPU I have is \_SB_.PCI0.PEG_.VID_
> but the power resource hooks are on \_SB_.PCI0.PEG_, so
> this patch creates a new power domain to turn the GPU
> device parent off using standard ACPI calls.
> 
> Signed-off-by: Dave Airlie <airlied@redhat.com>
> ---
>  drivers/gpu/vga/vga_switcheroo.c | 54 +++++++++++++++++++++++++++++++++++++++-
>  include/linux/vga_switcheroo.h   |  3 ++-
>  2 files changed, 55 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
> index 665ab9f..be32cb2 100644
> --- a/drivers/gpu/vga/vga_switcheroo.c
> +++ b/drivers/gpu/vga/vga_switcheroo.c
> @@ -42,7 +42,7 @@
>  #include <linux/uaccess.h>
>  #include <linux/vgaarb.h>
>  #include <linux/vga_switcheroo.h>
> -
> +#include <linux/acpi.h>
>  /**
>   * DOC: Overview
>   *
> @@ -997,3 +997,55 @@ vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device *dev,
>  	return -EINVAL;
>  }
>  EXPORT_SYMBOL(vga_switcheroo_init_domain_pm_optimus_hdmi_audio);
> +
> +/* With Windows 10 the runtime suspend/resume can use power
> +   resources on the parent device */
> +static int vga_acpi_switcheroo_runtime_suspend(struct device *dev)
> +{
> +	struct pci_dev *pdev = to_pci_dev(dev);
> +	int ret;
> +	struct acpi_device *adev;
> +
> +	ret = dev->bus->pm->runtime_suspend(dev);
> +	if (ret)
> +		return ret;
> +
> +	ret = acpi_bus_get_device(ACPI_HANDLE(&pdev->dev), &adev);
> +	if (!ret)
> +		acpi_device_set_power(adev->parent, ACPI_STATE_D3_COLD);
> +	return 0;
> +}
> +
> +static int vga_acpi_switcheroo_runtime_resume(struct device *dev)
> +{
> +	struct pci_dev *pdev = to_pci_dev(dev);
> +	struct acpi_device *adev;
> +	int ret;
> +
> +	ret = acpi_bus_get_device(ACPI_HANDLE(&pdev->dev), &adev);
> +	if (!ret)
> +		acpi_device_set_power(adev->parent, ACPI_STATE_D0);
> +	ret = dev->bus->pm->runtime_resume(dev);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +int vga_switcheroo_init_parent_pr3_ops(struct device *dev,
> +				       struct dev_pm_domain *domain)
> +
> +{
> +	/* copy over all the bus versions */
> +	if (dev->bus && dev->bus->pm) {
> +		domain->ops = *dev->bus->pm;
> +		domain->ops.runtime_suspend = vga_acpi_switcheroo_runtime_suspend;
> +		domain->ops.runtime_resume = vga_acpi_switcheroo_runtime_resume;
> +
> +		dev_pm_domain_set(dev, domain);
> +		return 0;
> +	}
> +	dev_pm_domain_set(dev, NULL);
> +	return -EINVAL;
> +}
> +EXPORT_SYMBOL(vga_switcheroo_init_parent_pr3_ops);
> diff --git a/include/linux/vga_switcheroo.h b/include/linux/vga_switcheroo.h
> index 69e1d4a1..5ce0cbe 100644
> --- a/include/linux/vga_switcheroo.h
> +++ b/include/linux/vga_switcheroo.h
> @@ -144,6 +144,7 @@ void vga_switcheroo_set_dynamic_switch(struct pci_dev *pdev, enum vga_switcheroo
>  int vga_switcheroo_init_domain_pm_ops(struct device *dev, struct dev_pm_domain *domain);
>  void vga_switcheroo_fini_domain_pm_ops(struct device *dev);
>  int vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device *dev, struct dev_pm_domain *domain);
> +int vga_switcheroo_init_parent_pr3_ops(struct device *dev, struct dev_pm_domain *domain);
>  #else
>  
>  static inline void vga_switcheroo_unregister_client(struct pci_dev *dev) {}
> @@ -163,6 +164,6 @@ static inline void vga_switcheroo_set_dynamic_switch(struct pci_dev *pdev, enum
>  static inline int vga_switcheroo_init_domain_pm_ops(struct device *dev, struct dev_pm_domain *domain) { return -EINVAL; }
>  static inline void vga_switcheroo_fini_domain_pm_ops(struct device *dev) {}
>  static inline int vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device *dev, struct dev_pm_domain *domain) { return -EINVAL; }
> -
> +static inline int vga_switcheroo_init_parent_pr3_ops(struct device *dev, struct dev_pm_domain *domain) { return -EINVAL; }
>  #endif
>  #endif /* _LINUX_VGA_SWITCHEROO_H_ */
> -- 
> 2.5.0
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Alex Deucher March 9, 2016, 4:52 p.m. UTC | #3
On Wed, Mar 9, 2016 at 9:33 AM, Lukas Wunner <lukas@wunner.de> wrote:
> Hi Dave,
>
> On Wed, Mar 09, 2016 at 04:14:04PM +1000, Dave Airlie wrote:
>> From: Dave Airlie <airlied@redhat.com>
>>
>> Windows 10 seems to have standardised power control for the
>> optimus/powerxpress laptops using PR3 power resource hooks.
>
> What happened to the Optimus DSM, does this still work? If not,
> echoing OFF to the vgaswitcheroo sysfs file won't power down the
> GPU now, right? (If runtime pm is disabled in nouveau.)
>

If the OS identifies itself as windows 10 or newer when initializing
ACPI, the standardized interfaces should be used if they exist.  I'm
not sure if there is any explicit policy on the vendor specific ones,
but I suspect they are probably broken in that case since I doubt the
OEM validates them when the standardized interfaces are available.

Alex

>> I'm not sure this is definitely the correct place to be
>> doing this, but it works for me here.
>
> How about implementing an additional vga_switcheroo handler somewhere
> in drivers/acpi/, which looks for the PR3 hooks and registers with
> vga_switcheroo if found. The ->power_state callback of that handler
> would then invoke acpi_device_set_power().
>
> The ACPI bus is scanned in the subsys_initcall section, much earlier
> than nouveau is loaded (in the device_initcall section). So the ACPI
> vga_switcheroo handler could register before the nouveau DSM handler
> and therefore would always have a higher precedence.
>
> In any case this patch should be amended with kerneldoc for
> vga_switcheroo_init_parent_pr3_ops(), I've spent considerable time
> last year to document everything and kindly ask that this water not
> be muddied again. ;-)
>
> One small nit, the headers are sorted alphabetically yet acpi.h is
> added at the end.
>
> Thanks,
>
> Lukas
>
>>
>> The ACPI device for the GPU I have is \_SB_.PCI0.PEG_.VID_
>> but the power resource hooks are on \_SB_.PCI0.PEG_, so
>> this patch creates a new power domain to turn the GPU
>> device parent off using standard ACPI calls.
>>
>> Signed-off-by: Dave Airlie <airlied@redhat.com>
>> ---
>>  drivers/gpu/vga/vga_switcheroo.c | 54 +++++++++++++++++++++++++++++++++++++++-
>>  include/linux/vga_switcheroo.h   |  3 ++-
>>  2 files changed, 55 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
>> index 665ab9f..be32cb2 100644
>> --- a/drivers/gpu/vga/vga_switcheroo.c
>> +++ b/drivers/gpu/vga/vga_switcheroo.c
>> @@ -42,7 +42,7 @@
>>  #include <linux/uaccess.h>
>>  #include <linux/vgaarb.h>
>>  #include <linux/vga_switcheroo.h>
>> -
>> +#include <linux/acpi.h>
>>  /**
>>   * DOC: Overview
>>   *
>> @@ -997,3 +997,55 @@ vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device *dev,
>>       return -EINVAL;
>>  }
>>  EXPORT_SYMBOL(vga_switcheroo_init_domain_pm_optimus_hdmi_audio);
>> +
>> +/* With Windows 10 the runtime suspend/resume can use power
>> +   resources on the parent device */
>> +static int vga_acpi_switcheroo_runtime_suspend(struct device *dev)
>> +{
>> +     struct pci_dev *pdev = to_pci_dev(dev);
>> +     int ret;
>> +     struct acpi_device *adev;
>> +
>> +     ret = dev->bus->pm->runtime_suspend(dev);
>> +     if (ret)
>> +             return ret;
>> +
>> +     ret = acpi_bus_get_device(ACPI_HANDLE(&pdev->dev), &adev);
>> +     if (!ret)
>> +             acpi_device_set_power(adev->parent, ACPI_STATE_D3_COLD);
>> +     return 0;
>> +}
>> +
>> +static int vga_acpi_switcheroo_runtime_resume(struct device *dev)
>> +{
>> +     struct pci_dev *pdev = to_pci_dev(dev);
>> +     struct acpi_device *adev;
>> +     int ret;
>> +
>> +     ret = acpi_bus_get_device(ACPI_HANDLE(&pdev->dev), &adev);
>> +     if (!ret)
>> +             acpi_device_set_power(adev->parent, ACPI_STATE_D0);
>> +     ret = dev->bus->pm->runtime_resume(dev);
>> +     if (ret)
>> +             return ret;
>> +
>> +     return 0;
>> +}
>> +
>> +int vga_switcheroo_init_parent_pr3_ops(struct device *dev,
>> +                                    struct dev_pm_domain *domain)
>> +
>> +{
>> +     /* copy over all the bus versions */
>> +     if (dev->bus && dev->bus->pm) {
>> +             domain->ops = *dev->bus->pm;
>> +             domain->ops.runtime_suspend = vga_acpi_switcheroo_runtime_suspend;
>> +             domain->ops.runtime_resume = vga_acpi_switcheroo_runtime_resume;
>> +
>> +             dev_pm_domain_set(dev, domain);
>> +             return 0;
>> +     }
>> +     dev_pm_domain_set(dev, NULL);
>> +     return -EINVAL;
>> +}
>> +EXPORT_SYMBOL(vga_switcheroo_init_parent_pr3_ops);
>> diff --git a/include/linux/vga_switcheroo.h b/include/linux/vga_switcheroo.h
>> index 69e1d4a1..5ce0cbe 100644
>> --- a/include/linux/vga_switcheroo.h
>> +++ b/include/linux/vga_switcheroo.h
>> @@ -144,6 +144,7 @@ void vga_switcheroo_set_dynamic_switch(struct pci_dev *pdev, enum vga_switcheroo
>>  int vga_switcheroo_init_domain_pm_ops(struct device *dev, struct dev_pm_domain *domain);
>>  void vga_switcheroo_fini_domain_pm_ops(struct device *dev);
>>  int vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device *dev, struct dev_pm_domain *domain);
>> +int vga_switcheroo_init_parent_pr3_ops(struct device *dev, struct dev_pm_domain *domain);
>>  #else
>>
>>  static inline void vga_switcheroo_unregister_client(struct pci_dev *dev) {}
>> @@ -163,6 +164,6 @@ static inline void vga_switcheroo_set_dynamic_switch(struct pci_dev *pdev, enum
>>  static inline int vga_switcheroo_init_domain_pm_ops(struct device *dev, struct dev_pm_domain *domain) { return -EINVAL; }
>>  static inline void vga_switcheroo_fini_domain_pm_ops(struct device *dev) {}
>>  static inline int vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device *dev, struct dev_pm_domain *domain) { return -EINVAL; }
>> -
>> +static inline int vga_switcheroo_init_parent_pr3_ops(struct device *dev, struct dev_pm_domain *domain) { return -EINVAL; }
>>  #endif
>>  #endif /* _LINUX_VGA_SWITCHEROO_H_ */
>> --
>> 2.5.0
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Lukas Wunner March 9, 2016, 8:17 p.m. UTC | #4
Hi,

On Wed, Mar 09, 2016 at 11:52:33AM -0500, Alex Deucher wrote:
> On Wed, Mar 9, 2016 at 9:33 AM, Lukas Wunner <lukas@wunner.de> wrote:
> > On Wed, Mar 09, 2016 at 04:14:04PM +1000, Dave Airlie wrote:
> >> From: Dave Airlie <airlied@redhat.com>
> >>
> >> Windows 10 seems to have standardised power control for the
> >> optimus/powerxpress laptops using PR3 power resource hooks.
> >
> > What happened to the Optimus DSM, does this still work? If not,
> > echoing OFF to the vgaswitcheroo sysfs file won't power down the
> > GPU now, right? (If runtime pm is disabled in nouveau.)
> >
> If the OS identifies itself as windows 10 or newer when initializing
> ACPI, the standardized interfaces should be used if they exist.  I'm
> not sure if there is any explicit policy on the vendor specific ones,
> but I suspect they are probably broken in that case since I doubt the
> OEM validates them when the standardized interfaces are available.

The vendor interface (Optimus DSM) must be present, otherwise the call
to nouveau_is_optimus() in patch [2/2] would return false.

But indeed it seems to not be working, otherwise why would the patches
be necessary?

My point is that the chosen approach does not square with vga_switcheroo's
architecture: Normally it's the handler's job to power the GPU up/down.
If runtime pm is enabled then vga_switcheroo_init_domain_pm_ops()
activates runtime_suspend/_resume callbacks which ask the handler to
flip the power switch.

However these two patches add *additional* runtime_suspend/_resume
callbacks which do not rely on the handler at all. The handler is thus
useless. This becomes apparent when loading the nouveau module with
runpm=0: Normally the user is then able to manually power the GPU
up/down by echoing ON or OFF to the vgaswitcheroo sysfs file. With the
chosen approach this will likely not work because the handler only knows
how to invoke the DSM, it doesn't know anything about PR3.

Hence my suggestion to solve this with an additional handler which
gets used in lieu of the nouveau DSM handler.

Best regards,

Lukas

> 
> Alex
> 
> >> I'm not sure this is definitely the correct place to be
> >> doing this, but it works for me here.
> >
> > How about implementing an additional vga_switcheroo handler somewhere
> > in drivers/acpi/, which looks for the PR3 hooks and registers with
> > vga_switcheroo if found. The ->power_state callback of that handler
> > would then invoke acpi_device_set_power().
> >
> > The ACPI bus is scanned in the subsys_initcall section, much earlier
> > than nouveau is loaded (in the device_initcall section). So the ACPI
> > vga_switcheroo handler could register before the nouveau DSM handler
> > and therefore would always have a higher precedence.
> >
> > In any case this patch should be amended with kerneldoc for
> > vga_switcheroo_init_parent_pr3_ops(), I've spent considerable time
> > last year to document everything and kindly ask that this water not
> > be muddied again. ;-)
> >
> > One small nit, the headers are sorted alphabetically yet acpi.h is
> > added at the end.
> >
> > Thanks,
> >
> > Lukas
> >
> >>
> >> The ACPI device for the GPU I have is \_SB_.PCI0.PEG_.VID_
> >> but the power resource hooks are on \_SB_.PCI0.PEG_, so
> >> this patch creates a new power domain to turn the GPU
> >> device parent off using standard ACPI calls.
> >>
> >> Signed-off-by: Dave Airlie <airlied@redhat.com>
> >> ---
> >>  drivers/gpu/vga/vga_switcheroo.c | 54 +++++++++++++++++++++++++++++++++++++++-
> >>  include/linux/vga_switcheroo.h   |  3 ++-
> >>  2 files changed, 55 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
> >> index 665ab9f..be32cb2 100644
> >> --- a/drivers/gpu/vga/vga_switcheroo.c
> >> +++ b/drivers/gpu/vga/vga_switcheroo.c
> >> @@ -42,7 +42,7 @@
> >>  #include <linux/uaccess.h>
> >>  #include <linux/vgaarb.h>
> >>  #include <linux/vga_switcheroo.h>
> >> -
> >> +#include <linux/acpi.h>
> >>  /**
> >>   * DOC: Overview
> >>   *
> >> @@ -997,3 +997,55 @@ vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device *dev,
> >>       return -EINVAL;
> >>  }
> >>  EXPORT_SYMBOL(vga_switcheroo_init_domain_pm_optimus_hdmi_audio);
> >> +
> >> +/* With Windows 10 the runtime suspend/resume can use power
> >> +   resources on the parent device */
> >> +static int vga_acpi_switcheroo_runtime_suspend(struct device *dev)
> >> +{
> >> +     struct pci_dev *pdev = to_pci_dev(dev);
> >> +     int ret;
> >> +     struct acpi_device *adev;
> >> +
> >> +     ret = dev->bus->pm->runtime_suspend(dev);
> >> +     if (ret)
> >> +             return ret;
> >> +
> >> +     ret = acpi_bus_get_device(ACPI_HANDLE(&pdev->dev), &adev);
> >> +     if (!ret)
> >> +             acpi_device_set_power(adev->parent, ACPI_STATE_D3_COLD);
> >> +     return 0;
> >> +}
> >> +
> >> +static int vga_acpi_switcheroo_runtime_resume(struct device *dev)
> >> +{
> >> +     struct pci_dev *pdev = to_pci_dev(dev);
> >> +     struct acpi_device *adev;
> >> +     int ret;
> >> +
> >> +     ret = acpi_bus_get_device(ACPI_HANDLE(&pdev->dev), &adev);
> >> +     if (!ret)
> >> +             acpi_device_set_power(adev->parent, ACPI_STATE_D0);
> >> +     ret = dev->bus->pm->runtime_resume(dev);
> >> +     if (ret)
> >> +             return ret;
> >> +
> >> +     return 0;
> >> +}
> >> +
> >> +int vga_switcheroo_init_parent_pr3_ops(struct device *dev,
> >> +                                    struct dev_pm_domain *domain)
> >> +
> >> +{
> >> +     /* copy over all the bus versions */
> >> +     if (dev->bus && dev->bus->pm) {
> >> +             domain->ops = *dev->bus->pm;
> >> +             domain->ops.runtime_suspend = vga_acpi_switcheroo_runtime_suspend;
> >> +             domain->ops.runtime_resume = vga_acpi_switcheroo_runtime_resume;
> >> +
> >> +             dev_pm_domain_set(dev, domain);
> >> +             return 0;
> >> +     }
> >> +     dev_pm_domain_set(dev, NULL);
> >> +     return -EINVAL;
> >> +}
> >> +EXPORT_SYMBOL(vga_switcheroo_init_parent_pr3_ops);
> >> diff --git a/include/linux/vga_switcheroo.h b/include/linux/vga_switcheroo.h
> >> index 69e1d4a1..5ce0cbe 100644
> >> --- a/include/linux/vga_switcheroo.h
> >> +++ b/include/linux/vga_switcheroo.h
> >> @@ -144,6 +144,7 @@ void vga_switcheroo_set_dynamic_switch(struct pci_dev *pdev, enum vga_switcheroo
> >>  int vga_switcheroo_init_domain_pm_ops(struct device *dev, struct dev_pm_domain *domain);
> >>  void vga_switcheroo_fini_domain_pm_ops(struct device *dev);
> >>  int vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device *dev, struct dev_pm_domain *domain);
> >> +int vga_switcheroo_init_parent_pr3_ops(struct device *dev, struct dev_pm_domain *domain);
> >>  #else
> >>
> >>  static inline void vga_switcheroo_unregister_client(struct pci_dev *dev) {}
> >> @@ -163,6 +164,6 @@ static inline void vga_switcheroo_set_dynamic_switch(struct pci_dev *pdev, enum
> >>  static inline int vga_switcheroo_init_domain_pm_ops(struct device *dev, struct dev_pm_domain *domain) { return -EINVAL; }
> >>  static inline void vga_switcheroo_fini_domain_pm_ops(struct device *dev) {}
> >>  static inline int vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device *dev, struct dev_pm_domain *domain) { return -EINVAL; }
> >> -
> >> +static inline int vga_switcheroo_init_parent_pr3_ops(struct device *dev, struct dev_pm_domain *domain) { return -EINVAL; }
> >>  #endif
> >>  #endif /* _LINUX_VGA_SWITCHEROO_H_ */
> >> --
> >> 2.5.0
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Alex Deucher March 9, 2016, 8:22 p.m. UTC | #5
On Wed, Mar 9, 2016 at 3:17 PM, Lukas Wunner <lukas@wunner.de> wrote:
> Hi,
>
> On Wed, Mar 09, 2016 at 11:52:33AM -0500, Alex Deucher wrote:
>> On Wed, Mar 9, 2016 at 9:33 AM, Lukas Wunner <lukas@wunner.de> wrote:
>> > On Wed, Mar 09, 2016 at 04:14:04PM +1000, Dave Airlie wrote:
>> >> From: Dave Airlie <airlied@redhat.com>
>> >>
>> >> Windows 10 seems to have standardised power control for the
>> >> optimus/powerxpress laptops using PR3 power resource hooks.
>> >
>> > What happened to the Optimus DSM, does this still work? If not,
>> > echoing OFF to the vgaswitcheroo sysfs file won't power down the
>> > GPU now, right? (If runtime pm is disabled in nouveau.)
>> >
>> If the OS identifies itself as windows 10 or newer when initializing
>> ACPI, the standardized interfaces should be used if they exist.  I'm
>> not sure if there is any explicit policy on the vendor specific ones,
>> but I suspect they are probably broken in that case since I doubt the
>> OEM validates them when the standardized interfaces are available.
>
> The vendor interface (Optimus DSM) must be present, otherwise the call
> to nouveau_is_optimus() in patch [2/2] would return false.
>
> But indeed it seems to not be working, otherwise why would the patches
> be necessary?

It may be present, but I doubt it's functional.  I can't speak for
nvidia's implementation, but for AMD, ATPX is present, but when you
parse the supported functions there is a flag saying that you need to
use the PR3 interface instead.  Maybe nvidia has something similar.
Then the driver could select whether to use the PR3 helpers or the
vendor specific interface.

Alex

>
> My point is that the chosen approach does not square with vga_switcheroo's
> architecture: Normally it's the handler's job to power the GPU up/down.
> If runtime pm is enabled then vga_switcheroo_init_domain_pm_ops()
> activates runtime_suspend/_resume callbacks which ask the handler to
> flip the power switch.
>
> However these two patches add *additional* runtime_suspend/_resume
> callbacks which do not rely on the handler at all. The handler is thus
> useless. This becomes apparent when loading the nouveau module with
> runpm=0: Normally the user is then able to manually power the GPU
> up/down by echoing ON or OFF to the vgaswitcheroo sysfs file. With the
> chosen approach this will likely not work because the handler only knows
> how to invoke the DSM, it doesn't know anything about PR3.
>
> Hence my suggestion to solve this with an additional handler which
> gets used in lieu of the nouveau DSM handler.
>
> Best regards,
>
> Lukas
>
>>
>> Alex
>>
>> >> I'm not sure this is definitely the correct place to be
>> >> doing this, but it works for me here.
>> >
>> > How about implementing an additional vga_switcheroo handler somewhere
>> > in drivers/acpi/, which looks for the PR3 hooks and registers with
>> > vga_switcheroo if found. The ->power_state callback of that handler
>> > would then invoke acpi_device_set_power().
>> >
>> > The ACPI bus is scanned in the subsys_initcall section, much earlier
>> > than nouveau is loaded (in the device_initcall section). So the ACPI
>> > vga_switcheroo handler could register before the nouveau DSM handler
>> > and therefore would always have a higher precedence.
>> >
>> > In any case this patch should be amended with kerneldoc for
>> > vga_switcheroo_init_parent_pr3_ops(), I've spent considerable time
>> > last year to document everything and kindly ask that this water not
>> > be muddied again. ;-)
>> >
>> > One small nit, the headers are sorted alphabetically yet acpi.h is
>> > added at the end.
>> >
>> > Thanks,
>> >
>> > Lukas
>> >
>> >>
>> >> The ACPI device for the GPU I have is \_SB_.PCI0.PEG_.VID_
>> >> but the power resource hooks are on \_SB_.PCI0.PEG_, so
>> >> this patch creates a new power domain to turn the GPU
>> >> device parent off using standard ACPI calls.
>> >>
>> >> Signed-off-by: Dave Airlie <airlied@redhat.com>
>> >> ---
>> >>  drivers/gpu/vga/vga_switcheroo.c | 54 +++++++++++++++++++++++++++++++++++++++-
>> >>  include/linux/vga_switcheroo.h   |  3 ++-
>> >>  2 files changed, 55 insertions(+), 2 deletions(-)
>> >>
>> >> diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
>> >> index 665ab9f..be32cb2 100644
>> >> --- a/drivers/gpu/vga/vga_switcheroo.c
>> >> +++ b/drivers/gpu/vga/vga_switcheroo.c
>> >> @@ -42,7 +42,7 @@
>> >>  #include <linux/uaccess.h>
>> >>  #include <linux/vgaarb.h>
>> >>  #include <linux/vga_switcheroo.h>
>> >> -
>> >> +#include <linux/acpi.h>
>> >>  /**
>> >>   * DOC: Overview
>> >>   *
>> >> @@ -997,3 +997,55 @@ vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device *dev,
>> >>       return -EINVAL;
>> >>  }
>> >>  EXPORT_SYMBOL(vga_switcheroo_init_domain_pm_optimus_hdmi_audio);
>> >> +
>> >> +/* With Windows 10 the runtime suspend/resume can use power
>> >> +   resources on the parent device */
>> >> +static int vga_acpi_switcheroo_runtime_suspend(struct device *dev)
>> >> +{
>> >> +     struct pci_dev *pdev = to_pci_dev(dev);
>> >> +     int ret;
>> >> +     struct acpi_device *adev;
>> >> +
>> >> +     ret = dev->bus->pm->runtime_suspend(dev);
>> >> +     if (ret)
>> >> +             return ret;
>> >> +
>> >> +     ret = acpi_bus_get_device(ACPI_HANDLE(&pdev->dev), &adev);
>> >> +     if (!ret)
>> >> +             acpi_device_set_power(adev->parent, ACPI_STATE_D3_COLD);
>> >> +     return 0;
>> >> +}
>> >> +
>> >> +static int vga_acpi_switcheroo_runtime_resume(struct device *dev)
>> >> +{
>> >> +     struct pci_dev *pdev = to_pci_dev(dev);
>> >> +     struct acpi_device *adev;
>> >> +     int ret;
>> >> +
>> >> +     ret = acpi_bus_get_device(ACPI_HANDLE(&pdev->dev), &adev);
>> >> +     if (!ret)
>> >> +             acpi_device_set_power(adev->parent, ACPI_STATE_D0);
>> >> +     ret = dev->bus->pm->runtime_resume(dev);
>> >> +     if (ret)
>> >> +             return ret;
>> >> +
>> >> +     return 0;
>> >> +}
>> >> +
>> >> +int vga_switcheroo_init_parent_pr3_ops(struct device *dev,
>> >> +                                    struct dev_pm_domain *domain)
>> >> +
>> >> +{
>> >> +     /* copy over all the bus versions */
>> >> +     if (dev->bus && dev->bus->pm) {
>> >> +             domain->ops = *dev->bus->pm;
>> >> +             domain->ops.runtime_suspend = vga_acpi_switcheroo_runtime_suspend;
>> >> +             domain->ops.runtime_resume = vga_acpi_switcheroo_runtime_resume;
>> >> +
>> >> +             dev_pm_domain_set(dev, domain);
>> >> +             return 0;
>> >> +     }
>> >> +     dev_pm_domain_set(dev, NULL);
>> >> +     return -EINVAL;
>> >> +}
>> >> +EXPORT_SYMBOL(vga_switcheroo_init_parent_pr3_ops);
>> >> diff --git a/include/linux/vga_switcheroo.h b/include/linux/vga_switcheroo.h
>> >> index 69e1d4a1..5ce0cbe 100644
>> >> --- a/include/linux/vga_switcheroo.h
>> >> +++ b/include/linux/vga_switcheroo.h
>> >> @@ -144,6 +144,7 @@ void vga_switcheroo_set_dynamic_switch(struct pci_dev *pdev, enum vga_switcheroo
>> >>  int vga_switcheroo_init_domain_pm_ops(struct device *dev, struct dev_pm_domain *domain);
>> >>  void vga_switcheroo_fini_domain_pm_ops(struct device *dev);
>> >>  int vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device *dev, struct dev_pm_domain *domain);
>> >> +int vga_switcheroo_init_parent_pr3_ops(struct device *dev, struct dev_pm_domain *domain);
>> >>  #else
>> >>
>> >>  static inline void vga_switcheroo_unregister_client(struct pci_dev *dev) {}
>> >> @@ -163,6 +164,6 @@ static inline void vga_switcheroo_set_dynamic_switch(struct pci_dev *pdev, enum
>> >>  static inline int vga_switcheroo_init_domain_pm_ops(struct device *dev, struct dev_pm_domain *domain) { return -EINVAL; }
>> >>  static inline void vga_switcheroo_fini_domain_pm_ops(struct device *dev) {}
>> >>  static inline int vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device *dev, struct dev_pm_domain *domain) { return -EINVAL; }
>> >> -
>> >> +static inline int vga_switcheroo_init_parent_pr3_ops(struct device *dev, struct dev_pm_domain *domain) { return -EINVAL; }
>> >>  #endif
>> >>  #endif /* _LINUX_VGA_SWITCHEROO_H_ */
>> >> --
>> >> 2.5.0
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Dave Airlie March 9, 2016, 9:56 p.m. UTC | #6
On 9 March 2016 at 23:19, Rafael J. Wysocki <rafael@kernel.org> wrote:
> On Wed, Mar 9, 2016 at 7:14 AM, Dave Airlie <airlied@gmail.com> wrote:
>> From: Dave Airlie <airlied@redhat.com>
>>
>> Windows 10 seems to have standardised power control for the
>> optimus/powerxpress laptops using PR3 power resource hooks.
>>
>> I'm not sure this is definitely the correct place to be
>> doing this, but it works for me here.
>>
>> The ACPI device for the GPU I have is \_SB_.PCI0.PEG_.VID_
>> but the power resource hooks are on \_SB_.PCI0.PEG_, so
>> this patch creates a new power domain to turn the GPU
>> device parent off using standard ACPI calls.
>>
>> Signed-off-by: Dave Airlie <airlied@redhat.com>
>> ---
>>  drivers/gpu/vga/vga_switcheroo.c | 54 +++++++++++++++++++++++++++++++++++++++-
>>  include/linux/vga_switcheroo.h   |  3 ++-
>>  2 files changed, 55 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
>> index 665ab9f..be32cb2 100644
>> --- a/drivers/gpu/vga/vga_switcheroo.c
>> +++ b/drivers/gpu/vga/vga_switcheroo.c
>> @@ -42,7 +42,7 @@
>>  #include <linux/uaccess.h>
>>  #include <linux/vgaarb.h>
>>  #include <linux/vga_switcheroo.h>
>> -
>> +#include <linux/acpi.h>
>>  /**
>>   * DOC: Overview
>>   *
>> @@ -997,3 +997,55 @@ vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device *dev,
>>         return -EINVAL;
>>  }
>>  EXPORT_SYMBOL(vga_switcheroo_init_domain_pm_optimus_hdmi_audio);
>> +
>> +/* With Windows 10 the runtime suspend/resume can use power
>> +   resources on the parent device */
>> +static int vga_acpi_switcheroo_runtime_suspend(struct device *dev)
>> +{
>> +       struct pci_dev *pdev = to_pci_dev(dev);
>> +       int ret;
>> +       struct acpi_device *adev;
>> +
>> +       ret = dev->bus->pm->runtime_suspend(dev);
>> +       if (ret)
>> +               return ret;
>> +
>> +       ret = acpi_bus_get_device(ACPI_HANDLE(&pdev->dev), &adev);
>
> You can use ACPI_COMPANION(&pdev->dev) for that.
>
>> +       if (!ret)
>> +               acpi_device_set_power(adev->parent, ACPI_STATE_D3_COLD);
>
> Won't that mess up with the PM of the parent?  Or do we know that the
> parent won't do its own PM?

The parent is always going to be pcieport. It doesn't seem to do any runtime PM,
I do wonder if pcieport should be doing it's own runtime PM handling,
but that is a
larger task than I'm thinking to tackle here. Maybe I should be doing

pci_set_power_state(pdev->bus->self, PCI_D3cold) ? I'm not really sure.

I'm guessing on Windows this all happens automatically.

Dave.
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Dave Airlie March 9, 2016, 10 p.m. UTC | #7
On 10 March 2016 at 00:33, Lukas Wunner <lukas@wunner.de> wrote:
> Hi Dave,
>
> On Wed, Mar 09, 2016 at 04:14:04PM +1000, Dave Airlie wrote:
>> From: Dave Airlie <airlied@redhat.com>
>>
>> Windows 10 seems to have standardised power control for the
>> optimus/powerxpress laptops using PR3 power resource hooks.
>
> What happened to the Optimus DSM, does this still work? If not,
> echoing OFF to the vgaswitcheroo sysfs file won't power down the
> GPU now, right? (If runtime pm is disabled in nouveau.)

No it doesn't work, hence why I had to go dig through this method. When
you report Windows 2013 ACPI support to the BIOS it disables the PS3 method,
and relies on hitting the PR3 method. Unlike ATPX I couldn't find any
indicator bit
in the optimus DSM to say which method to use. So we get to try both methods.

I've confirmed on my older machine that if there are no PR3 methods, then it
has no effect.

> How about implementing an additional vga_switcheroo handler somewhere
> in drivers/acpi/, which looks for the PR3 hooks and registers with
> vga_switcheroo if found. The ->power_state callback of that handler
> would then invoke acpi_device_set_power().

I've nothing to trigger off when to register in that case. I'm not
sure if the PR3
hooks alone are enough to tell you whether you should be using this method.
The ATPX guys have a bit we need to read to know if we should be using this
method.

>
> In any case this patch should be amended with kerneldoc for
> vga_switcheroo_init_parent_pr3_ops(), I've spent considerable time
> last year to document everything and kindly ask that this water not
> be muddied again. ;-)
>
> One small nit, the headers are sorted alphabetically yet acpi.h is
> added at the end.

I'll add those in v2.

Dave.
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Dave Airlie March 9, 2016, 10:02 p.m. UTC | #8
On 10 March 2016 at 06:17, Lukas Wunner <lukas@wunner.de> wrote:
> Hi,
>
> On Wed, Mar 09, 2016 at 11:52:33AM -0500, Alex Deucher wrote:
>> On Wed, Mar 9, 2016 at 9:33 AM, Lukas Wunner <lukas@wunner.de> wrote:
>> > On Wed, Mar 09, 2016 at 04:14:04PM +1000, Dave Airlie wrote:
>> >> From: Dave Airlie <airlied@redhat.com>
>> >>
>> >> Windows 10 seems to have standardised power control for the
>> >> optimus/powerxpress laptops using PR3 power resource hooks.
>> >
>> > What happened to the Optimus DSM, does this still work? If not,
>> > echoing OFF to the vgaswitcheroo sysfs file won't power down the
>> > GPU now, right? (If runtime pm is disabled in nouveau.)
>> >
>> If the OS identifies itself as windows 10 or newer when initializing
>> ACPI, the standardized interfaces should be used if they exist.  I'm
>> not sure if there is any explicit policy on the vendor specific ones,
>> but I suspect they are probably broken in that case since I doubt the
>> OEM validates them when the standardized interfaces are available.
>
> The vendor interface (Optimus DSM) must be present, otherwise the call
> to nouveau_is_optimus() in patch [2/2] would return false.
>
> But indeed it seems to not be working, otherwise why would the patches
> be necessary?
>
> My point is that the chosen approach does not square with vga_switcheroo's
> architecture: Normally it's the handler's job to power the GPU up/down.
> If runtime pm is enabled then vga_switcheroo_init_domain_pm_ops()
> activates runtime_suspend/_resume callbacks which ask the handler to
> flip the power switch.
>
> However these two patches add *additional* runtime_suspend/_resume
> callbacks which do not rely on the handler at all. The handler is thus
> useless. This becomes apparent when loading the nouveau module with
> runpm=0: Normally the user is then able to manually power the GPU
> up/down by echoing ON or OFF to the vgaswitcheroo sysfs file. With the
> chosen approach this will likely not work because the handler only knows
> how to invoke the DSM, it doesn't know anything about PR3.
>
> Hence my suggestion to solve this with an additional handler which
> gets used in lieu of the nouveau DSM handler.

I'll think about this a bit more, but really I don't care for vgaswitcheroo
manual power control anymore. It's in debugfs for a reason, it was a stopgap
until we got dynamic power control.

If dynamic power control isn't working for some people we should fix that,
but supporting nouveau.runpm=0 and manual power control is so far down
the list of things I care about.

Dave.
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Rafael J. Wysocki March 10, 2016, 8:57 p.m. UTC | #9
On Thursday, March 10, 2016 07:56:41 AM Dave Airlie wrote:
> On 9 March 2016 at 23:19, Rafael J. Wysocki <rafael@kernel.org> wrote:
> > On Wed, Mar 9, 2016 at 7:14 AM, Dave Airlie <airlied@gmail.com> wrote:
> >> From: Dave Airlie <airlied@redhat.com>
> >>
> >> Windows 10 seems to have standardised power control for the
> >> optimus/powerxpress laptops using PR3 power resource hooks.
> >>
> >> I'm not sure this is definitely the correct place to be
> >> doing this, but it works for me here.
> >>
> >> The ACPI device for the GPU I have is \_SB_.PCI0.PEG_.VID_
> >> but the power resource hooks are on \_SB_.PCI0.PEG_, so
> >> this patch creates a new power domain to turn the GPU
> >> device parent off using standard ACPI calls.
> >>
> >> Signed-off-by: Dave Airlie <airlied@redhat.com>
> >> ---
> >>  drivers/gpu/vga/vga_switcheroo.c | 54 +++++++++++++++++++++++++++++++++++++++-
> >>  include/linux/vga_switcheroo.h   |  3 ++-
> >>  2 files changed, 55 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
> >> index 665ab9f..be32cb2 100644
> >> --- a/drivers/gpu/vga/vga_switcheroo.c
> >> +++ b/drivers/gpu/vga/vga_switcheroo.c
> >> @@ -42,7 +42,7 @@
> >>  #include <linux/uaccess.h>
> >>  #include <linux/vgaarb.h>
> >>  #include <linux/vga_switcheroo.h>
> >> -
> >> +#include <linux/acpi.h>
> >>  /**
> >>   * DOC: Overview
> >>   *
> >> @@ -997,3 +997,55 @@ vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device *dev,
> >>         return -EINVAL;
> >>  }
> >>  EXPORT_SYMBOL(vga_switcheroo_init_domain_pm_optimus_hdmi_audio);
> >> +
> >> +/* With Windows 10 the runtime suspend/resume can use power
> >> +   resources on the parent device */
> >> +static int vga_acpi_switcheroo_runtime_suspend(struct device *dev)
> >> +{
> >> +       struct pci_dev *pdev = to_pci_dev(dev);
> >> +       int ret;
> >> +       struct acpi_device *adev;
> >> +
> >> +       ret = dev->bus->pm->runtime_suspend(dev);
> >> +       if (ret)
> >> +               return ret;
> >> +
> >> +       ret = acpi_bus_get_device(ACPI_HANDLE(&pdev->dev), &adev);
> >
> > You can use ACPI_COMPANION(&pdev->dev) for that.
> >
> >> +       if (!ret)
> >> +               acpi_device_set_power(adev->parent, ACPI_STATE_D3_COLD);
> >
> > Won't that mess up with the PM of the parent?  Or do we know that the
> > parent won't do its own PM?
> 
> The parent is always going to be pcieport.

I see.

> It doesn't seem to do any runtime PM,
> I do wonder if pcieport should be doing it's own runtime PM handling,
> but that is a
> larger task than I'm thinking to tackle here.

PCIe ports don't do PM - yet.  Mika has posted a series of patches to implement
that, however, that are waiting for comments now:

https://patchwork.kernel.org/patch/8453311/
https://patchwork.kernel.org/patch/8453381/
https://patchwork.kernel.org/patch/8453391/
https://patchwork.kernel.org/patch/8453411/
https://patchwork.kernel.org/patch/8453371/
https://patchwork.kernel.org/patch/8453351/

> Maybe I should be doing
> 
> pci_set_power_state(pdev->bus->self, PCI_D3cold) ? I'm not really sure.

Using pci_set_power_state() would be more appropriate IMO, but you can get
to the bridge via dev->parent too, can't you?

In any case, it looks like you and Mika need to talk. :-)

> I'm guessing on Windows this all happens automatically.

PCIe ports are power-managend by (newer) Windows AFAICS, but we know for a fact
that this simply doesn't work reliably on some older hardware which is why
we don't do that.  I suppose that the Windows in question uses a cut-off date
or similar to decide what do do with PCIe ports PM.

Thanks,
Rafael

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Mika Westerberg March 11, 2016, 10:58 a.m. UTC | #10
On Thu, Mar 10, 2016 at 09:57:09PM +0100, Rafael J. Wysocki wrote:
> > It doesn't seem to do any runtime PM,
> > I do wonder if pcieport should be doing it's own runtime PM handling,
> > but that is a
> > larger task than I'm thinking to tackle here.
> 
> PCIe ports don't do PM - yet.  Mika has posted a series of patches to implement
> that, however, that are waiting for comments now:
> 
> https://patchwork.kernel.org/patch/8453311/
> https://patchwork.kernel.org/patch/8453381/
> https://patchwork.kernel.org/patch/8453391/
> https://patchwork.kernel.org/patch/8453411/
> https://patchwork.kernel.org/patch/8453371/
> https://patchwork.kernel.org/patch/8453351/
> 
> > Maybe I should be doing
> > 
> > pci_set_power_state(pdev->bus->self, PCI_D3cold) ? I'm not really sure.
> 
> Using pci_set_power_state() would be more appropriate IMO, but you can get
> to the bridge via dev->parent too, can't you?
> 
> In any case, it looks like you and Mika need to talk. :-)

When the vga_switcheroo device gets runtime suspended (with the above
runtime PM patchs for PCIe root ports) the root port should also be
runtime suspended by the PM core. I don't think there is a need to call
any pci_set_power_state() in this driver but maybe I'm missing
something.
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Rafael J. Wysocki March 11, 2016, 1:45 p.m. UTC | #11
On Friday, March 11, 2016 12:58:15 PM Mika Westerberg wrote:
> On Thu, Mar 10, 2016 at 09:57:09PM +0100, Rafael J. Wysocki wrote:
> > > It doesn't seem to do any runtime PM,
> > > I do wonder if pcieport should be doing it's own runtime PM handling,
> > > but that is a
> > > larger task than I'm thinking to tackle here.
> > 
> > PCIe ports don't do PM - yet.  Mika has posted a series of patches to implement
> > that, however, that are waiting for comments now:
> > 
> > https://patchwork.kernel.org/patch/8453311/
> > https://patchwork.kernel.org/patch/8453381/
> > https://patchwork.kernel.org/patch/8453391/
> > https://patchwork.kernel.org/patch/8453411/
> > https://patchwork.kernel.org/patch/8453371/
> > https://patchwork.kernel.org/patch/8453351/
> > 
> > > Maybe I should be doing
> > > 
> > > pci_set_power_state(pdev->bus->self, PCI_D3cold) ? I'm not really sure.
> > 
> > Using pci_set_power_state() would be more appropriate IMO, but you can get
> > to the bridge via dev->parent too, can't you?
> > 
> > In any case, it looks like you and Mika need to talk. :-)
> 
> When the vga_switcheroo device gets runtime suspended (with the above
> runtime PM patchs for PCIe root ports) the root port should also be
> runtime suspended by the PM core.

Right, after your patches have been applied, the additional handling
won't be needed.

So Dave, maybe you can check if the Mika's patches help?

Thanks,
Rafael

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diff mbox

Patch

diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
index 665ab9f..be32cb2 100644
--- a/drivers/gpu/vga/vga_switcheroo.c
+++ b/drivers/gpu/vga/vga_switcheroo.c
@@ -42,7 +42,7 @@ 
 #include <linux/uaccess.h>
 #include <linux/vgaarb.h>
 #include <linux/vga_switcheroo.h>
-
+#include <linux/acpi.h>
 /**
  * DOC: Overview
  *
@@ -997,3 +997,55 @@  vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device *dev,
 	return -EINVAL;
 }
 EXPORT_SYMBOL(vga_switcheroo_init_domain_pm_optimus_hdmi_audio);
+
+/* With Windows 10 the runtime suspend/resume can use power
+   resources on the parent device */
+static int vga_acpi_switcheroo_runtime_suspend(struct device *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	int ret;
+	struct acpi_device *adev;
+
+	ret = dev->bus->pm->runtime_suspend(dev);
+	if (ret)
+		return ret;
+
+	ret = acpi_bus_get_device(ACPI_HANDLE(&pdev->dev), &adev);
+	if (!ret)
+		acpi_device_set_power(adev->parent, ACPI_STATE_D3_COLD);
+	return 0;
+}
+
+static int vga_acpi_switcheroo_runtime_resume(struct device *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	struct acpi_device *adev;
+	int ret;
+
+	ret = acpi_bus_get_device(ACPI_HANDLE(&pdev->dev), &adev);
+	if (!ret)
+		acpi_device_set_power(adev->parent, ACPI_STATE_D0);
+	ret = dev->bus->pm->runtime_resume(dev);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+int vga_switcheroo_init_parent_pr3_ops(struct device *dev,
+				       struct dev_pm_domain *domain)
+
+{
+	/* copy over all the bus versions */
+	if (dev->bus && dev->bus->pm) {
+		domain->ops = *dev->bus->pm;
+		domain->ops.runtime_suspend = vga_acpi_switcheroo_runtime_suspend;
+		domain->ops.runtime_resume = vga_acpi_switcheroo_runtime_resume;
+
+		dev_pm_domain_set(dev, domain);
+		return 0;
+	}
+	dev_pm_domain_set(dev, NULL);
+	return -EINVAL;
+}
+EXPORT_SYMBOL(vga_switcheroo_init_parent_pr3_ops);
diff --git a/include/linux/vga_switcheroo.h b/include/linux/vga_switcheroo.h
index 69e1d4a1..5ce0cbe 100644
--- a/include/linux/vga_switcheroo.h
+++ b/include/linux/vga_switcheroo.h
@@ -144,6 +144,7 @@  void vga_switcheroo_set_dynamic_switch(struct pci_dev *pdev, enum vga_switcheroo
 int vga_switcheroo_init_domain_pm_ops(struct device *dev, struct dev_pm_domain *domain);
 void vga_switcheroo_fini_domain_pm_ops(struct device *dev);
 int vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device *dev, struct dev_pm_domain *domain);
+int vga_switcheroo_init_parent_pr3_ops(struct device *dev, struct dev_pm_domain *domain);
 #else
 
 static inline void vga_switcheroo_unregister_client(struct pci_dev *dev) {}
@@ -163,6 +164,6 @@  static inline void vga_switcheroo_set_dynamic_switch(struct pci_dev *pdev, enum
 static inline int vga_switcheroo_init_domain_pm_ops(struct device *dev, struct dev_pm_domain *domain) { return -EINVAL; }
 static inline void vga_switcheroo_fini_domain_pm_ops(struct device *dev) {}
 static inline int vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device *dev, struct dev_pm_domain *domain) { return -EINVAL; }
-
+static inline int vga_switcheroo_init_parent_pr3_ops(struct device *dev, struct dev_pm_domain *domain) { return -EINVAL; }
 #endif
 #endif /* _LINUX_VGA_SWITCHEROO_H_ */