diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c index 21291950cc97..26bc05e48d8a 100644 --- a/drivers/usb/core/config.c +++ b/drivers/usb/core/config.c @@ -392,12 +392,16 @@ static int usb_parse_endpoint(struct device *ddev, int cfgno, endpoint->desc.wMaxPacketSize = cpu_to_le16(8); } - /* Validate the wMaxPacketSize field */ + /* + * Validate the wMaxPacketSize field. + * Some devices have isochronous endpoints in altsetting 0; + * the USB-2 spec requires such endpoints to have wMaxPacketSize = 0 + * (see the end of section 5.6.3), so don't warn about them. + */ maxp = usb_endpoint_maxp(&endpoint->desc); - if (maxp == 0) { - dev_warn(ddev, "config %d interface %d altsetting %d endpoint 0x%X has wMaxPacketSize 0, skipping\n", + if (maxp == 0 && !(usb_endpoint_xfer_isoc(d) && asnum == 0)) { + dev_warn(ddev, "config %d interface %d altsetting %d endpoint 0x%X has invalid wMaxPacketSize 0\n", cfgno, inum, asnum, d->bEndpointAddress); - goto skip_to_next_endpoint_or_interface_descriptor; } /* Find the highest legal maxpacket size for this endpoint */