usb: retry reset if a device times out

Some devices I got show an inability to operate right after
power on if they are already connected. They are beyond recovery
if the descriptors are requested multiple times. So in case of
a timeout we rather bail early and reset again. But it must be
done only on the first loop lest we get into a reset/time out
spiral that can be overcome with a retry.

This patch is a rework of a patch that fell through the cracks.
http://www.spinics.net/lists/linux-usb/msg103263.html

Signed-off-by: Oliver Neukum <oneukum@suse.com>
CC: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 681036d005289e86c044d0f19fe003aa12174a40..0f82db42fd5957210058ed869b5316c6c142adeb 100644 (file)
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -4496,7 +4496,13 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1,
                                                r = -EPROTO;
                                        break;
                                }
-                               if (r == 0)
+                               /*
+                                * Some devices time out if they are powered on
+                                * when already connected. They need a second
+                                * reset. But only on the first attempt,
+                                * lest we get into a time out/reset loop
+                                */
+                               if (r == 0  || (r == -ETIMEDOUT && j == 0))
                                        break;
                        }
                        udev->descriptor.bMaxPacketSize0 =