Re: [PATCH 2/3] xhci: Add zhaoxin xHCI U1/U2 feature support

[WeitaoWang-oc@xxxxxxxxxxx]

On 2023/4/20 17:39, Sergei Shtylyov wrote:
> On 4/20/23 8:21 PM, Weitao Wang wrote:
>
> > Add U1/U2 feature support of xHCI for zhaoxin.
> >
> > Signed-off-by: Weitao Wang <WeitaoWang-oc@xxxxxxxxxxx>
> [...]
>
> > diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> > index 6307bae9cddf..730c0f68518d 100644
> > --- a/drivers/usb/host/xhci.c
> > +++ b/drivers/usb/host/xhci.c
> [...]
> > @@ -4938,6 +4938,27 @@ static int xhci_update_timeout_for_interface(struct xhci_hcd *xhci,
> >   	return 0;
> >   }
> >   
> > +static int xhci_check_zhaoxin_tier_policy(struct usb_device *udev,
> > +		enum usb3_link_state state)
> > +{
> > +	struct usb_device *parent;
> > +	unsigned int num_hubs;
> > +
> > +	/* Don't enable U1/U2 if the device is on an external hub. */
> > +	for (parent = udev->parent, num_hubs = 0; parent->parent;
> > +			parent = parent->parent)
> > +		num_hubs++;
> > +
> > +	if (num_hubs < 1)
> > +		return 0;
> > +
> > +	dev_dbg(&udev->dev, "Disabling U1/U2 link state for device"
> > +			" below external hub.\n");
> > +	dev_dbg(&udev->dev, "Plug device into root hub "
> > +			"to decrease power consumption.\n");
>
>     Please don't break up the message strings.

Thanks for your advice, and I will merge this message in next patch version.
> [...]
> > @@ -4965,6 +4986,8 @@ static int xhci_check_tier_policy(struct xhci_hcd *xhci,
> >   {
> >   	if (xhci->quirks & XHCI_INTEL_HOST)
> >   		return xhci_check_intel_tier_policy(udev, state);
> > +	else if (xhci->quirks & XHCI_ZHAOXIN_HOST)
>
>     *else* not needed after *return*.
This function need a "int" type return value. If remove "else" branch,
vendor other than intel and zhaoxin will not get a return value.

Best Regards,
Weitao

> > +		return xhci_check_zhaoxin_tier_policy(udev, state);
> >   	else
> >   		return 0;
> >   }
>
> MBR, Sergey
> .