Author: hselasky
Date: Tue Oct 20 08:34:03 2020
New Revision: 366887
URL: https://svnweb.freebsd.org/changeset/base/366887
Log:
MFC r366536:
Try a bit harder to get the USB device descriptor in case the initial read
fails.
Sponsored by: Mellanox Technologies // NVIDIA Networking
Modified:
stable/11/sys/dev/usb/usb_request.c
Directory Properties:
stable/11/ (props changed)
Modified: stable/11/sys/dev/usb/usb_request.c
==============================================================================
--- stable/11/sys/dev/usb/usb_request.c Tue Oct 20 08:33:11 2020
(r366886)
+++ stable/11/sys/dev/usb/usb_request.c Tue Oct 20 08:34:03 2020
(r366887)
@@ -1970,9 +1970,23 @@ usbd_setup_device_desc(struct usb_device *udev, struct
/* get partial device descriptor, some devices crash on this */
err = usbd_req_get_desc(udev, mtx, NULL, &udev->ddesc,
USB_MAX_IPACKET, USB_MAX_IPACKET, 0, UDESC_DEVICE, 0, 0);
- if (err != 0)
- break;
-
+ if (err != 0) {
+ DPRINTF("Trying fallback for getting the USB device
descriptor\n");
+ /* try 8 bytes bMaxPacketSize */
+ udev->ddesc.bMaxPacketSize = 8;
+ /* get full device descriptor */
+ err = usbd_req_get_device_desc(udev, mtx, &udev->ddesc);
+ if (err == 0)
+ break;
+ /* try 16 bytes bMaxPacketSize */
+ udev->ddesc.bMaxPacketSize = 16;
+ /* get full device descriptor */
+ err = usbd_req_get_device_desc(udev, mtx, &udev->ddesc);
+ if (err == 0)
+ break;
+ /* try 32/64 bytes bMaxPacketSize */
+ udev->ddesc.bMaxPacketSize = 32;
+ }
/* get the full device descriptor */
err = usbd_req_get_device_desc(udev, mtx, &udev->ddesc);
break;
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