On Thu, May 30, 2019 at 04:50:39PM +0800, 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: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
> Cc: Jun Li <jun.li@xxxxxxx>
> Signed-off-by: Peter Chen <peter.chen@xxxxxxx>
> ---
> Changes for v2:
> - Improve the code sytle
>
> drivers/usb/chipidea/udc.c | 23 +++++++++++++++++++++++
> 1 file changed, 23 insertions(+)
>
> diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
> index 829e947cabf5..21c1344bfc42 100644
> --- a/drivers/usb/chipidea/udc.c
> +++ b/drivers/usb/chipidea/udc.c
> @@ -1622,6 +1622,28 @@ 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 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) &&
usb_endpoint_xfer_isoc()?
> + (desc->bEndpointAddress & USB_DIR_IN)) {
usb_endpoint_dir_in()?
thanks,
greg k-h
