Subject: Re: linux-next: manual merge of the pm tree with the pci-current tree

From: Bjorn Helgaas <[email-masked]>
Date: Tue, 20 Feb 2024 09:36:16 -0600

On Wed, Feb 14, 2024 at 10:30:08AM +1100, Stephen Rothwell wrote:
> Hi all,
> 
> Today's linux-next merge of the pm tree got a conflict in:
> 
>   drivers/pci/pci.c
> 
> between commit:
> 
>   41044d536068 ("PCI: Fix active state requirement in PME polling")
> 
> from the pci-current tree and commit:
> 
>   c0ef3df8dbae ("PM: runtime: Simplify pm_runtime_get_if_active() usage")
> 
> from the pm tree.

Just FYI, 41044d536068 is now upstream for v6.8, so the conflict will
be between upstream and the pm tree:

https://git.kernel.org/linus/41044d536068

> I fixed it up (see below) and can carry the fix as necessary. This
> is now fixed as far as linux-next is concerned, but any non trivial
> conflicts should be mentioned to your upstream maintainer when your tree
> is submitted for merging.  You may also want to consider cooperating
> with the maintainer of the conflicting tree to minimise any particularly
> complex conflicts.
> 
> -- 
> Cheers,
> Stephen Rothwell
> 
> diff --cc drivers/pci/pci.c
> index a532bf597e57,cb51c4079013..000000000000
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@@ -2361,36 -2522,29 +2361,36 @@@ static void pci_pme_list_scan(struct wo
>   		if (pdev->pme_poll) {
>   			struct pci_dev *bridge = pdev->bus->self;
>   			struct device *dev = &pdev->dev;
>  -			int pm_status;
>  +			struct device *bdev = bridge ? &bridge->dev : NULL;
>  +			int bref = 0;
>   
>   			/*
>  -			 * If bridge is in low power state, the
>  -			 * configuration space of subordinate devices
>  -			 * may be not accessible
>  +			 * If we have a bridge, it should be in an active/D0
>  +			 * state or the configuration space of subordinate
>  +			 * devices may not be accessible or stable over the
>  +			 * course of the call.
>   			 */
>  -			if (bridge && bridge->current_state != PCI_D0)
>  -				continue;
>  +			if (bdev) {
> - 				bref = pm_runtime_get_if_active(bdev, true);
> ++				bref = pm_runtime_get_if_active(bdev);
>  +				if (!bref)
>  +					continue;
>  +
>  +				if (bridge->current_state != PCI_D0)
>  +					goto put_bridge;
>  +			}
>   
>   			/*
>  -			 * If the device is in a low power state it
>  -			 * should not be polled either.
>  +			 * The device itself should be suspended but config
>  +			 * space must be accessible, therefore it cannot be in
>  +			 * D3cold.
>   			 */
>  -			pm_status = pm_runtime_get_if_active(dev);
>  -			if (!pm_status)
>  -				continue;
>  -
>  -			if (pdev->current_state != PCI_D3cold)
>  +			if (pm_runtime_suspended(dev) &&
>  +			    pdev->current_state != PCI_D3cold)
>   				pci_pme_wakeup(pdev, NULL);
>   
>  -			if (pm_status > 0)
>  -				pm_runtime_put(dev);
>  +put_bridge:
>  +			if (bref > 0)
>  +				pm_runtime_put(bdev);
>   		} else {
>   			list_del(&pme_dev->list);
>   			kfree(pme_dev);