For isoc endpoint descriptor, the wMaxPacketSize is not real max packet size (see Table 9-13. Standard Endpoint Descriptor, USB 2.0 specifcation), it may contain the number of packet, so the real max packet should be ep->desc->wMaxPacketSize && 0x7ff. Cc: Felipe F. Tonello <eu@xxxxxxxxxxxxxxxxx> Cc: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx> Fixes: 16b114a6d797 ("usb: gadget: fix usb_ep_align_maybe endianness and new usb_ep_aligna") Signed-off-by: Peter Chen <peter.chen@xxxxxxx> --- include/linux/usb/gadget.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h index 8e81f9e..cce2db6 100644 --- a/include/linux/usb/gadget.h +++ b/include/linux/usb/gadget.h @@ -429,7 +429,10 @@ static inline struct usb_gadget *dev_to_usb_gadget(struct device *dev) */ static inline size_t usb_ep_align(struct usb_ep *ep, size_t len) { - return round_up(len, (size_t)le16_to_cpu(ep->desc->wMaxPacketSize)); + int max_packet_size = (size_t)le16_to_cpu(ep->desc->wMaxPacketSize) + && 0x7ff; + + return round_up(len, max_packet_size); } /** -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html