Re: [PATCH 5/6] mhi: pci_generic: Use generic PCI power management

[Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>]

On Mon, Mar 01, 2021 at 05:25:10PM +0100, Loic Poulain wrote:
> The PCI core can take care of proper PCI suspend/resume operations, but
> this is discarded when the driver saves PCI state by its own. This
> currently prevents the PCI core to enable PME (for modem initiated
> D3 exit) which is requested for proper runtime pm support.
> 
> This change deletes explicit PCI state-saving and state-set from
> suspend callback, letting the PCI doing the appropriate work.
> 
> Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
> ---
>  drivers/bus/mhi/pci_generic.c | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/bus/mhi/pci_generic.c b/drivers/bus/mhi/pci_generic.c
> index 8423293..2a66f80 100644
> --- a/drivers/bus/mhi/pci_generic.c
> +++ b/drivers/bus/mhi/pci_generic.c
> @@ -544,9 +544,12 @@ static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>  
>  	pci_set_drvdata(pdev, mhi_pdev);
>  
> -	/* Have stored pci confspace at hand for restore in sudden PCI error */
> +	/* Have stored pci confspace at hand for restore in sudden PCI error.
> +	 * cache the state locally and discard the PCI core one.
> +	 */
>  	pci_save_state(pdev);
>  	mhi_pdev->pci_state = pci_store_saved_state(pdev);
> +	pci_load_saved_state(pdev, NULL);

Why do you need to load the state here?

Thanks,
Mani

>  
>  	pci_enable_pcie_error_reporting(pdev);
>  
> @@ -717,10 +720,8 @@ static int  __maybe_unused mhi_pci_suspend(struct device *dev)
>  	/* Transition to M3 state */
>  	mhi_pm_suspend(mhi_cntrl);
>  
> -	pci_save_state(pdev);
>  	pci_disable_device(pdev);
>  	pci_wake_from_d3(pdev, true);
> -	pci_set_power_state(pdev, PCI_D3hot);
>  
>  	return 0;
>  }
> @@ -732,14 +733,13 @@ static int __maybe_unused mhi_pci_resume(struct device *dev)
>  	struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;
>  	int err;
>  
> -	pci_set_power_state(pdev, PCI_D0);
> -	pci_restore_state(pdev);
> -	pci_set_master(pdev);
> -
>  	err = pci_enable_device(pdev);
>  	if (err)
>  		goto err_recovery;
>  
> +	pci_set_master(pdev);
> +	pci_wake_from_d3(pdev, false);
> +
>  	/* Exit M3, transition to M0 state */
>  	err = mhi_pm_resume(mhi_cntrl);
>  	if (err) {
> -- 
> 2.7.4
>