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

[Rafael J. Wysocki]

On Wed, Mar 9, 2016 at 7:14 AM, Dave Airlie <airlied@xxxxxxxxx> wrote:
> From: Dave Airlie <airlied@xxxxxxxxxx>
>
> 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@xxxxxxxxxx>
> ---
>  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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