Re: [PATCH] PCI: Stop setting cached power state to "unknown" on unbind

[Mario Limonciello <superm1@kernel.org>]

On 4/17/26 03:51, Lukas Wunner wrote:
> When a PCI device is unbound from its driver, pci_device_remove() sets the
> cached power state in pci_dev->current_state to PCI_UNKNOWN.  This was
> introduced by commit 2449e06a5696 ("PCI: reset pci device state to unknown
> state for resume") to invalidate the cached power state in case the system
> is subsequently put to sleep.
> 
> For bound devices, the cached power state is set to PCI_UNKNOWN in
> pci_pm_suspend_noirq(), immediately before entering system sleep.
> 
> Extend to unbound devices for consistency.
> 
> This obviates the need to change the cached power state on unbind, so stop
> doing so.
> 
> Signed-off-by: Lukas Wunner <lukas@wunner.de>

Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>

FWIW I also had review-prompts /kreview check for corner cases and it 
didn't find any.

> ---
>   drivers/pci/pci-driver.c | 10 ++--------
>   1 file changed, 2 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
> index 7c2d9d5..774892d 100644
> --- a/drivers/pci/pci-driver.c
> +++ b/drivers/pci/pci-driver.c
> @@ -482,13 +482,6 @@ static void pci_device_remove(struct device *dev)
>   	pm_runtime_put_sync(dev);
>   
>   	/*
> -	 * If the device is still on, set the power state as "unknown",
> -	 * since it might change by the next time we load the driver.
> -	 */
> -	if (pci_dev->current_state == PCI_D0)
> -		pci_dev->current_state = PCI_UNKNOWN;
> -
> -	/*
>   	 * We would love to complain here if pci_dev->is_enabled is set, that
>   	 * the driver should have called pci_disable_device(), but the
>   	 * unfortunate fact is there are too many odd BIOS and bridge setups
> @@ -862,7 +855,7 @@ static int pci_pm_suspend_noirq(struct device *dev)
>   
>   	if (!pm) {
>   		pci_save_state(pci_dev);
> -		goto Fixup;
> +		goto set_unknown;
>   	}
>   
>   	if (pm->suspend_noirq) {
> @@ -914,6 +907,7 @@ static int pci_pm_suspend_noirq(struct device *dev)
>   		goto Fixup;
>   	}
>   
> +set_unknown:
>   	pci_pm_set_unknown_state(pci_dev);
>   
>   	/*