Re: [PATCH 2/2] xhci: Enable RPM on controllers that support low-power states

[Mathias Nyman <mathias.nyman@linux.intel.com>]

On 21.8.2023 9.57, Basavaraj Natikar wrote:
> Use the low-power states of the underlying platform to enable runtime PM.
> If the platform doesn't support runtime D3, then enabling default RPM will
> result in the controller malfunctioning, as in the case of hotplug devices
> not being detected because of a failed interrupt generation.
> 
> Cc: Mario Limonciello <mario.limonciello@amd.com>
> Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
> ---
>   drivers/usb/host/xhci-pci.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
> index c908a80ef436..1bb5b510c5ba 100644
> --- a/drivers/usb/host/xhci-pci.c
> +++ b/drivers/usb/host/xhci-pci.c
> @@ -693,7 +693,9 @@ static int xhci_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
>   	/* USB-2 and USB-3 roothubs initialized, allow runtime pm suspend */
>   	pm_runtime_put_noidle(&dev->dev);
>   
> -	if (xhci->quirks & XHCI_DEFAULT_PM_RUNTIME_ALLOW)
> +	if (pci_choose_state(dev, PMSG_SUSPEND) == PCI_D0)
> +		pm_runtime_forbid(&dev->dev);
> +	else if (xhci->quirks & XHCI_DEFAULT_PM_RUNTIME_ALLOW)
>   		pm_runtime_allow(&dev->dev);
>   
>   	dma_set_max_seg_size(&dev->dev, UINT_MAX);

Looks good to me

-Mathias