Re: [PATCH v2 5/6] drm/i915/pm: Allow drivers/pci to manage our pci state normally

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Tue, Mar 11, 2025 at 09:56:23PM +0200, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> Stop doing the pci_save_state(), except when we need to prevent
> D3 due to BIOS bugs, so that the code in drivers/pci is allowed
> to manage the state of the PCI device. Less chance something
> getting left by the wayside by i915 if/when the things change in
> drivers/pci.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/i915_driver.c | 11 +++++------
>  1 file changed, 5 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_driver.c b/drivers/gpu/drm/i915/i915_driver.c
> index a199e21c7bb4..503f1b6b694f 100644
> --- a/drivers/gpu/drm/i915/i915_driver.c
> +++ b/drivers/gpu/drm/i915/i915_driver.c
> @@ -1154,9 +1154,8 @@ static int i915_drm_suspend_noirq(struct drm_device *dev, bool hibernation)
>  	 * pci_save_state() prevents drivers/pci from
>  	 * automagically putting the device into D3.
>  	 */
> -	pci_save_state(pdev);
> -	if (!(hibernation && GRAPHICS_VER(dev_priv) < 6))
> -		pci_set_power_state(pdev, PCI_D3hot);
> +	if (hibernation && GRAPHICS_VER(dev_priv) < 6)
> +		pci_save_state(pdev);
>  
>  	return 0;
>  }
> @@ -1164,6 +1163,7 @@ static int i915_drm_suspend_noirq(struct drm_device *dev, bool hibernation)
>  int i915_driver_suspend_switcheroo(struct drm_i915_private *i915,
>  				   pm_message_t state)
>  {
> +	struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
>  	int error;
>  
>  	if (drm_WARN_ON_ONCE(&i915->drm, state.event != PM_EVENT_SUSPEND &&
> @@ -1181,9 +1181,8 @@ int i915_driver_suspend_switcheroo(struct drm_i915_private *i915,
>  	if (error)
>  		return error;
>  
> -	error = i915_drm_suspend_noirq(&i915->drm, false);
> -	if (error)
> -		return error;
> +	pci_save_state(pdev);
> +	pci_set_power_state(pdev, PCI_D3hot);

Cc: Badal Nilawar <badal.nilawar@intel.com>

he hit an issue in Xe recently related to the lack of this iirc.
Hopefully this is right here and we can get this right here and port to Xe.

>  
>  	return 0;
>  }
> -- 
> 2.45.3
>