Re: [PATCH v3] xhci: Use pm_runtime_get to prevent RPM on unsupported systems

[Mario Limonciello <mario.limonciello@amd.com>]

On 10/24/2024 08:37, Basavaraj Natikar wrote:
> Use pm_runtime_put in the remove function and pm_runtime_get to disable
> RPM on platforms that don't support runtime D3, as re-enabling it through
> sysfs auto power control may cause the controller to malfunction. This
> can lead to issues such as hotplug devices not being detected due to
> failed interrupt generation.
> 
> Fixes: a5d6264b638e ("xhci: Enable RPM on controllers that support low-power states")
> Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>

Cc: stable@vger.kernel.org
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>

> ---
> v2->v3:
>   * Respinned v3 with an updated changelog.
> v1->v2:
>   * Used pm_runtime_get and updated the subject line accordingly.
> ---
>   drivers/usb/host/xhci-pci.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
> index 7e538194a0a4..cb07cee9ed0c 100644
> --- a/drivers/usb/host/xhci-pci.c
> +++ b/drivers/usb/host/xhci-pci.c
> @@ -640,7 +640,7 @@ int xhci_pci_common_probe(struct pci_dev *dev, const struct pci_device_id *id)
>   	pm_runtime_put_noidle(&dev->dev);
>   
>   	if (pci_choose_state(dev, PMSG_SUSPEND) == PCI_D0)
> -		pm_runtime_forbid(&dev->dev);
> +		pm_runtime_get(&dev->dev);
>   	else if (xhci->quirks & XHCI_DEFAULT_PM_RUNTIME_ALLOW)
>   		pm_runtime_allow(&dev->dev);
>   
> @@ -683,7 +683,9 @@ void xhci_pci_remove(struct pci_dev *dev)
>   
>   	xhci->xhc_state |= XHCI_STATE_REMOVING;
>   
> -	if (xhci->quirks & XHCI_DEFAULT_PM_RUNTIME_ALLOW)
> +	if (pci_choose_state(dev, PMSG_SUSPEND) == PCI_D0)
> +		pm_runtime_put(&dev->dev);
> +	else if (xhci->quirks & XHCI_DEFAULT_PM_RUNTIME_ALLOW)
>   		pm_runtime_forbid(&dev->dev);
>   
>   	if (xhci->shared_hcd) {