Re: [Linux-kernel-mentees] [PATCH v1 2/2] realtek/8139cp: Remove Legacy Power Management

[Bjorn Helgaas <helgaas@kernel.org>]

On Thu, Apr 23, 2020 at 06:58:01PM +0530, Vaibhav Gupta wrote:
> Upgrade Power Management from legacy to generic using dev_pm_ops.
> 
> Remove pci_save_sate(), pci_set_state(), etc. No need of directive
> '#ifdef CONFIG_PM' as, if CONFIG_PM is not defined, the binding
> will be by deafult set to NULL.

s/deafult/default/

I didn't quite follow this argument.  SIMPLE_DEV_PM_OPS() is defined
to SET_SYSTEM_SLEEP_PM_OPS(), and SET_SYSTEM_SLEEP_PM_OPS() is defined
to nothing unless CONFIG_PM_SLEEP (not CONFIG_PM).

But in any case, we don't want cp_suspend() and cp_resume() to be
compiled at all if they're not referenced.  So I think converting the
"#ifdef CONFIG_PM" to "#ifdef CONFIG_PM_SLEEP" is the right thing.

> Signed-off-by: Vaibhav Gupta <vaibhavgupta40@gmail.com>
> ---
>  drivers/net/ethernet/realtek/8139cp.c | 25 +++++++------------------
>  1 file changed, 7 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/net/ethernet/realtek/8139cp.c b/drivers/net/ethernet/realtek/8139cp.c
> index 60d342f82fb3..e2e79cf4e1fa 100644
> --- a/drivers/net/ethernet/realtek/8139cp.c
> +++ b/drivers/net/ethernet/realtek/8139cp.c
> @@ -2054,10 +2054,9 @@ static void cp_remove_one (struct pci_dev *pdev)
>  	free_netdev(dev);
>  }
>  
> -#ifdef CONFIG_PM
> -static int cp_suspend (struct pci_dev *pdev, pm_message_t state)
> +static int cp_suspend(struct device *device)
>  {
> -	struct net_device *dev = pci_get_drvdata(pdev);
> +	struct net_device *dev = dev_get_drvdata(device);
>  	struct cp_private *cp = netdev_priv(dev);
>  	unsigned long flags;
>  
> @@ -2075,16 +2074,12 @@ static int cp_suspend (struct pci_dev *pdev, pm_message_t state)
>  
>  	spin_unlock_irqrestore (&cp->lock, flags);
>  
> -	pci_save_state(pdev);
> -	pci_enable_wake(pdev, pci_choose_state(pdev, state), cp->wol_enabled);
> -	pci_set_power_state(pdev, pci_choose_state(pdev, state));
> -
>  	return 0;
>  }
>  
> -static int cp_resume (struct pci_dev *pdev)
> +static int cp_resume(struct device *device)
>  {
> -	struct net_device *dev = pci_get_drvdata (pdev);
> +	struct net_device *dev = dev_get_drvdata(device);
>  	struct cp_private *cp = netdev_priv(dev);
>  	unsigned long flags;
>  
> @@ -2093,10 +2088,6 @@ static int cp_resume (struct pci_dev *pdev)
>  
>  	netif_device_attach (dev);
>  
> -	pci_set_power_state(pdev, PCI_D0);
> -	pci_restore_state(pdev);
> -	pci_enable_wake(pdev, PCI_D0, 0);
> -
>  	/* FIXME: sh*t may happen if the Rx ring buffer is depleted */
>  	cp_init_rings_index (cp);
>  	cp_init_hw (cp);
> @@ -2111,7 +2102,6 @@ static int cp_resume (struct pci_dev *pdev)
>  
>  	return 0;
>  }
> -#endif /* CONFIG_PM */
>  
>  static const struct pci_device_id cp_pci_tbl[] = {
>          { PCI_DEVICE(PCI_VENDOR_ID_REALTEK,     PCI_DEVICE_ID_REALTEK_8139), },
> @@ -2120,15 +2110,14 @@ static const struct pci_device_id cp_pci_tbl[] = {
>  };
>  MODULE_DEVICE_TABLE(pci, cp_pci_tbl);
>  
> +static SIMPLE_DEV_PM_OPS(cp_pm_ops, cp_suspend, cp_resume);
> +
>  static struct pci_driver cp_driver = {
>  	.name         = DRV_NAME,
>  	.id_table     = cp_pci_tbl,
>  	.probe        =	cp_init_one,
>  	.remove       = cp_remove_one,
> -#ifdef CONFIG_PM
> -	.resume       = cp_resume,
> -	.suspend      = cp_suspend,
> -#endif
> +	.driver.pm    = &cp_pm_ops,
>  };
>  
>  module_pci_driver(cp_driver);
> -- 
> 2.26.2
> 
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