Re: [Intel-gfx] [PATCH] drm/i915/dgfx: Disable d3cold Correctly

["Nilawar, Badal" <badal.nilawar@intel.com>]

On 06-06-2022 17:56, Anshuman Gupta wrote:
> Currently i915 disables d3cold for i915 pci dev.
> This blocks D3 for i915 gfx pci upstream bridge (VSP).
> Let's disable d3cold at gfx root port to make sure that
> i915 gfx VSP can transition to D3 to save some power.
> 
> Fixes: 1a085e23411d ("drm/i915: Disable D3Cold in s2idle and runtime pm")
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
> ---
>   drivers/gpu/drm/i915/i915_driver.c | 34 +++++++++++++-----------------
>   1 file changed, 15 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_driver.c b/drivers/gpu/drm/i915/i915_driver.c
> index d26dcca7e654..86f9f0be76a6 100644
> --- a/drivers/gpu/drm/i915/i915_driver.c
> +++ b/drivers/gpu/drm/i915/i915_driver.c
> @@ -546,6 +546,7 @@ static int i915_pcode_init(struct drm_i915_private *i915)
>   static int i915_driver_hw_probe(struct drm_i915_private *dev_priv)
>   {
>   	struct pci_dev *pdev = to_pci_dev(dev_priv->drm.dev);
> +	struct pci_dev *root_pdev;
>   	int ret;
>   
>   	if (i915_inject_probe_failure(dev_priv))
> @@ -657,6 +658,15 @@ static int i915_driver_hw_probe(struct drm_i915_private *dev_priv)
>   
>   	intel_bw_init_hw(dev_priv);
>   
> +	/*
> +	 * FIXME: Temporary hammer to avoid freezing the machine on our DGFX
> +	 * This should be totally removed when we handle the pci states properly
> +	 * on runtime PM and on s2idle cases.
> +	 */
> +	root_pdev = pcie_find_root_port(pdev);
> +	if (root_pdev)
> +		pci_d3cold_disable(root_pdev);
> +
>   	return 0;
>   
>   err_msi:
> @@ -680,11 +690,16 @@ static int i915_driver_hw_probe(struct drm_i915_private *dev_priv)
>   static void i915_driver_hw_remove(struct drm_i915_private *dev_priv)
>   {
>   	struct pci_dev *pdev = to_pci_dev(dev_priv->drm.dev);
> +	struct pci_dev *root_pdev;
>   
>   	i915_perf_fini(dev_priv);
>   
>   	if (pdev->msi_enabled)
>   		pci_disable_msi(pdev);
> +
> +	root_pdev = pcie_find_root_port(pdev);
> +	if (root_pdev)
> +		pci_d3cold_enable(root_pdev);
>   }
This looks good to me.

Reviewed-by: Badal Nilawar <badal.nilawar@intel.com>

Regards,
Badal Nilawar
>   
>   /**
> @@ -1209,14 +1224,6 @@ static int i915_drm_suspend_late(struct drm_device *dev, bool hibernation)
>   		goto out;
>   	}
>   
> -	/*
> -	 * FIXME: Temporary hammer to avoid freezing the machine on our DGFX
> -	 * This should be totally removed when we handle the pci states properly
> -	 * on runtime PM and on s2idle cases.
> -	 */
> -	if (suspend_to_idle(dev_priv))
> -		pci_d3cold_disable(pdev);
> -
>   	pci_disable_device(pdev);
>   	/*
>   	 * During hibernation on some platforms the BIOS may try to access
> @@ -1381,8 +1388,6 @@ static int i915_drm_resume_early(struct drm_device *dev)
>   
>   	pci_set_master(pdev);
>   
> -	pci_d3cold_enable(pdev);
> -
>   	disable_rpm_wakeref_asserts(&dev_priv->runtime_pm);
>   
>   	ret = vlv_resume_prepare(dev_priv, false);
> @@ -1559,7 +1564,6 @@ static int intel_runtime_suspend(struct device *kdev)
>   {
>   	struct drm_i915_private *dev_priv = kdev_to_i915(kdev);
>   	struct intel_runtime_pm *rpm = &dev_priv->runtime_pm;
> -	struct pci_dev *pdev = to_pci_dev(dev_priv->drm.dev);
>   	int ret;
>   
>   	if (drm_WARN_ON_ONCE(&dev_priv->drm, !HAS_RUNTIME_PM(dev_priv)))
> @@ -1605,12 +1609,6 @@ static int intel_runtime_suspend(struct device *kdev)
>   		drm_err(&dev_priv->drm,
>   			"Unclaimed access detected prior to suspending\n");
>   
> -	/*
> -	 * FIXME: Temporary hammer to avoid freezing the machine on our DGFX
> -	 * This should be totally removed when we handle the pci states properly
> -	 * on runtime PM and on s2idle cases.
> -	 */
> -	pci_d3cold_disable(pdev);
>   	rpm->suspended = true;
>   
>   	/*
> @@ -1649,7 +1647,6 @@ static int intel_runtime_resume(struct device *kdev)
>   {
>   	struct drm_i915_private *dev_priv = kdev_to_i915(kdev);
>   	struct intel_runtime_pm *rpm = &dev_priv->runtime_pm;
> -	struct pci_dev *pdev = to_pci_dev(dev_priv->drm.dev);
>   	int ret;
>   
>   	if (drm_WARN_ON_ONCE(&dev_priv->drm, !HAS_RUNTIME_PM(dev_priv)))
> @@ -1662,7 +1659,6 @@ static int intel_runtime_resume(struct device *kdev)
>   
>   	intel_opregion_notify_adapter(dev_priv, PCI_D0);
>   	rpm->suspended = false;
> -	pci_d3cold_enable(pdev);
>   	if (intel_uncore_unclaimed_mmio(&dev_priv->uncore))
>   		drm_dbg(&dev_priv->drm,
>   			"Unclaimed access during suspend, bios?\n");