On Mon, May 27, 2019 at 5:04 PM Sergei Shtylyov
<sergei.shtylyov@xxxxxxxxxxxxxxxxxx> wrote:
>
> On 27.05.2019 10:42, Peter Chen wrote:
>
> > An endpoint conflict occurs when the USB is working in device mode
> > during an isochronous communication. When the endpointA IN direction
> > is an isochronous IN endpoint, and the host sends an IN token to
> > endpointA on another device, then the OUT transaction may be missed
> > regardless the OUT endpoint number. Generally, this occurs when the
> > device is connected to the host through a hub and other devices are
> > connected to the same hub.
> >
> > The affected OUT endpoint can be either control, bulk, isochronous, or
> > an interrupt endpoint. After the OUT endpoint is primed, if an IN token
> > to the same endpoint number on another device is received, then the OUT
> > endpoint may be unprimed (cannot be detected by software), which causes
> > this endpoint to no longer respond to the host OUT token, and thus, no
> > corresponding interrupt occurs.
> >
> > There is no good workaround for this issue, the only thing the software
> > could do is numbering isochronous IN from the highest endpoint since we
> > have observed most of device number endpoint from the lowest.
> >
> > Cc: <stable@xxxxxxxxxxxxxxx> #v3.14+
> > Cc: Jun Li <jun.li@xxxxxxx>
> > Signed-off-by: Peter Chen <peter.chen@xxxxxxx>
> > ---
> > drivers/usb/chipidea/udc.c | 24 ++++++++++++++++++++++++
> > 1 file changed, 24 insertions(+)
> >
> > diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
> > index 829e947cabf5..411d387a45c9 100644
> > --- a/drivers/usb/chipidea/udc.c
> > +++ b/drivers/usb/chipidea/udc.c
> > @@ -1622,6 +1622,29 @@ static int ci_udc_pullup(struct usb_gadget *_gadget, int is_on)
> > static int ci_udc_start(struct usb_gadget *gadget,
> > struct usb_gadget_driver *driver);
> > static int ci_udc_stop(struct usb_gadget *gadget);
> > +
> > +
> > +/* Match ISOC IN from the highest endpoint */
> > +static struct
>
> Um, please break the line before the function's type is fully described.
>
> > +usb_ep *ci_udc_match_ep(struct usb_gadget *gadget,
> > + struct usb_endpoint_descriptor *desc,
> > + struct usb_ss_ep_comp_descriptor *comp_desc)
> > +{
> > + struct ci_hdrc *ci = container_of(gadget, struct ci_hdrc, gadget);
> > + struct usb_ep *ep;
> > + u8 type = desc->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK;
> > +
> > + if ((type == USB_ENDPOINT_XFER_ISOC) &&
> > + (desc->bEndpointAddress & USB_DIR_IN)) {
>
> Please add 1 more tab here, so that this line doesn't blend with the
> following statement.
>
> > + list_for_each_entry_reverse(ep, &ci->gadget.ep_list, ep_list) {
> > + if (ep->caps.dir_in && !ep->claimed)
> > + return ep;
> > + }
> > + }
> > +
> > + return NULL;
> > +}
> > +
> > /**
> > * Device operations part of the API to the USB controller hardware,
> > * which don't involve endpoints (or i/o)
Will change both comments, thanks.
Peter
