diff options
| -rw-r--r-- | sys/dev/usb/usb_request.c | 29 |
1 files changed, 27 insertions, 2 deletions
diff --git a/sys/dev/usb/usb_request.c b/sys/dev/usb/usb_request.c index 29d9368ac413..fa5c469406cb 100644 --- a/sys/dev/usb/usb_request.c +++ b/sys/dev/usb/usb_request.c @@ -990,7 +990,7 @@ usbd_req_get_desc(struct usb_device *udev, uint8_t retries) { struct usb_device_request req; - uint8_t *buf; + uint8_t *buf = desc; usb_error_t err; DPRINTFN(4, "id=%d, type=%d, index=%d, max_len=%d\n", @@ -1012,6 +1012,32 @@ usbd_req_get_desc(struct usb_device *udev, err = usbd_do_request_flags(udev, mtx, &req, desc, 0, NULL, 500 /* ms */); + if (err != 0 && err != USB_ERR_TIMEOUT && + min_len != max_len) { + /* clear descriptor data */ + memset(desc, 0, max_len); + + /* try to read full descriptor length */ + USETW(req.wLength, max_len); + + err = usbd_do_request_flags(udev, mtx, &req, + desc, USB_SHORT_XFER_OK, NULL, 500 /* ms */); + + if (err == 0) { + /* verify length */ + if (buf[0] > max_len) + buf[0] = max_len; + else if (buf[0] < 2) + err = USB_ERR_INVAL; + + min_len = buf[0]; + + /* enforce descriptor type */ + buf[1] = type; + goto done; + } + } + if (err) { if (!retries) { goto done; @@ -1022,7 +1048,6 @@ usbd_req_get_desc(struct usb_device *udev, continue; } - buf = desc; if (min_len == max_len) { |