1 files changed, 16 insertions, 0 deletions

diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index 737e3c19967b..71dc5d768fa5 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -742,6 +742,22 @@ static int check_ctrlrecip(struct dev_state *ps, unsigned int requesttype,
                 if ((index & ~USB_DIR_IN) == 0)
                         return 0;
                 ret = findintfep(ps->dev, index);
+                if (ret < 0) {
+                        /*
+                         * Some not fully compliant Win apps seem to get
+                         * index wrong and have the endpoint number here
+                         * rather than the endpoint address (with the
+                         * correct direction). Win does let this through,
+                         * so we'll not reject it here but leave it to
+                         * the device to not break KVM. But we warn.
+                         */
+                        ret = findintfep(ps->dev, index ^ 0x80);
+                        if (ret >= 0)
+                                dev_info(&ps->dev->dev,
+                                        "%s: process %i (%s) requesting ep %02x but needs %02x\n",
+                                        __func__, task_pid_nr(current),
+                                        current->comm, index, index ^ 0x80);
+                }
                 if (ret >= 0)
                         ret = checkintf(ps, ret);
                 break;