On Mon, Jul 09, 2012 at 09:57:57AM -0700, Greg KH wrote:
> On Sat, Jul 07, 2012 at 10:56:45PM +0800, Richard Zhao wrote:
> > Phy may need to change settings when port connect change.
> >
> > Signed-off-by: Richard Zhao <richard.zhao@xxxxxxxxxxxxx>
> > Tested-by: Subodh Nijsure <snijsure@xxxxxxxxxxxx>
> > ---
> > drivers/usb/core/hub.c | 8 ++++++++
> > 1 file changed, 8 insertions(+)
> >
> > diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> > index 4cc8dc9..2ba9d84 100644
> > --- a/drivers/usb/core/hub.c
> > +++ b/drivers/usb/core/hub.c
> > @@ -20,6 +20,7 @@
> > #include <linux/usb.h>
> > #include <linux/usbdevice_fs.h>
> > #include <linux/usb/hcd.h>
> > +#include <linux/usb/otg.h>
> > #include <linux/usb/quirks.h>
> > #include <linux/kthread.h>
> > #include <linux/mutex.h>
> > @@ -4037,6 +4038,13 @@ static void hub_port_connect_change(struct usb_hub *hub, int port1,
> > }
> > }
> >
> > + if (unlikely(hcd->phy && !hdev->parent)) {
>
> Why is this "unlikely"? And why mark it as such, is this a "fast path"
> that needs the compiler to know this hint to optimize things here?
>
> Please don't use likely() or unlikely() except in places it really is
> needed, _and_ you have measured the difference. Have you done so in
> this place?
It's from a comment by Alan Stern.
http://www.spinics.net/lists/linux-usb/msg64987.html
Actually, for my board, it's not unlikely. But for others which don't
have notify_connect/disconnect, it's unlikely.
Because it's not unlikely for all boards, I prefer remove "unlikely".
Thanks
Richard
>
> thanks,
>
> greg k-h
>
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