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

[WeitaoWang-oc@xxxxxxxxxxx]

On 2023/4/20 22:22, Sergei Shtylyov wrote:
> On 4/20/23 11:21 PM, WeitaoWang-oc@xxxxxxxxxxx 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.
>
>     I didn't tell you to remove the whole branch, just the *else* keyword.

I understand what you mean this time. Here's code needs more concise.
I'll try to do more think and test.Thanks again!

weitao
> [...]
> > Best Regards,
> > Weitao
>
> MBR, Sergey
> .