Date: Wed, 27 Jun 2018 12:08:12 +0000 (UTC) From: Hans Petter Selasky <hselasky@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r335700 - head/sys/dev/usb Message-ID: <201806271208.w5RC8CNa021860@repo.freebsd.org>
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Author: hselasky Date: Wed Jun 27 12:08:12 2018 New Revision: 335700 URL: https://svnweb.freebsd.org/changeset/base/335700 Log: Improve the kernel's USB descriptor reading function. Some USB devices does not allow a partial descriptor readout. Found by: bz@ MFC after: 1 week Sponsored by: Mellanox Technologies Modified: head/sys/dev/usb/usb_request.c Modified: head/sys/dev/usb/usb_request.c ============================================================================== --- head/sys/dev/usb/usb_request.c Wed Jun 27 07:24:07 2018 (r335699) +++ head/sys/dev/usb/usb_request.c Wed Jun 27 12:08:12 2018 (r335700) @@ -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) {
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