[U-Boot] [U-Boot,v3,7/8] usb: hub: Reset only usb 2.0 ports

[Vivek Gautam]

On Wed, Apr 24, 2013 at 5:51 AM, Marek Vasut <marex at denx.de> wrote:
> Dear Julius Werner,
>
>> Sorry, forgot this one yesterday. I would consider to just drop/revert
>> this patch entirely. It's not wrong, but it adds complexity where it is
>> not needed. You don't have to reset SuperSpeed devices, but it shouldn't
>> hurt either and from what I can tell Linux does it as well.
>
> Ok, I can drop this one.

Alright, we will drop this.
I think a possible bug related to calling xhci_port_state_to_neutral()
in xhci_submit_root()
(one pointed by Julius in [PATCH v3 3/8] usb: hub: Power-cycle on
root-hub ports) was causing
USB 3.0 protocol ports fail while resetting.
Now things are fine.

>
>> > As per XHCI specifications USB 3.0 protocol ports attempt
>> > to advance to 'Enabled' state; however USB 2.0 protocol ports
>> > require software reset to advance them to 'Enabled' state.
>> > Thereby, inferring that software need to reset USB 2.0 protocol
>> > ports invariably (as per EHCI spec or xHCI spec).
>> >
>> > Signed-off-by: Vivek Gautam <gautam.vivek at samsung.com>
>> >
>> > ---
>> > This patch added in V3(current-version) of this patch-series.
>> >
>> >  common/usb_hub.c |   23 +++++++++++++++++++----
>> >  1 files changed, 19 insertions(+), 4 deletions(-)
>> >
>> > diff --git a/common/usb_hub.c b/common/usb_hub.c
>> > index 1e225e6..eedbcf2 100644
>> > --- a/common/usb_hub.c
>> > +++ b/common/usb_hub.c
>> > @@ -233,6 +233,7 @@ void usb_hub_port_connect_change(struct usb_device
>> > *dev, int port)
>> >
>> >     struct usb_device *usb;
>> >     ALLOC_CACHE_ALIGN_BUFFER(struct usb_port_status, portsts, 1);
>> >     unsigned short portstatus;
>> >
>> > +   uint32_t do_port_reset = 1;
>> >
>> >     /* Check status */
>> >     if (usb_get_port_status(dev, port + 1, portsts) < 0) {
>> >
>> > @@ -246,6 +247,9 @@ void usb_hub_port_connect_change(struct usb_device
>> > *dev, int port)
>> >
>> >           le16_to_cpu(portsts->wPortChange),
>> >           portspeed(portstatus));
>> >
>> > +   if (portstatus & (1 << USB_PORT_FEAT_SUPERSPEED))
>> > +           do_port_reset = 0;
>> > +
>> >
>> >     /* Clear the connection change status */
>> >     usb_clear_port_feature(dev, port + 1, USB_PORT_FEAT_C_CONNECTION);
>> >
>> > @@ -259,10 +263,21 @@ void usb_hub_port_connect_change(struct usb_device
>> > *dev, int port)
>> >
>> >     }
>> >     mdelay(200);
>> >
>> > -   /* Reset the port */
>> > -   if (hub_port_reset(dev, port, &portstatus) < 0) {
>> > -           printf("cannot reset port %i!?\n", port + 1);
>> > -           return;
>> > +   /*
>> > +    * Reset the port:
>> > +    * As per xHCI protocol, USB 3.0 devices do not require
>> > +    * a port reset, however USB 2.0 device do require the same
>> > +    * to let ports proceed to 'enabled' state
>> > +    *
>> > +    * XXX: Will this break EHCI ??
>> > +    * probably not, above condition for 'do_port_reset' checks for
>> > +    * speed, and for EHCI it can't reach Super speed anyways.
>> > +    */
>> > +   if (do_port_reset) {
>> > +           if (hub_port_reset(dev, port, &portstatus) < 0) {
>> > +                   printf("cannot reset port %i!?\n", port + 1);
>> > +                   return;
>> > +           }
>> >
>> >     }
>> >
>> >     mdelay(200);
>
> Best regards,
> Marek Vasut
> _______________________________________________
> U-Boot mailing list
> U-Boot at lists.denx.de
> http://lists.denx.de/mailman/listinfo/u-boot



-- 
Best Regards
Vivek