USB: fix toggle mismatch in disable_endpoint paths

This patch (as1200) finishes some fixes that were left incomplete by
an earlier patch.

Although nobody has addressed this issue in the past, it turns out
that we need to distinguish between two different modes of disabling
and enabling endpoints.  In one mode only the data structures in
usbcore are affected, and in the other mode the host controller and
device hardware states are affected as well.

The earlier patch added an extra argument to the routines in the
enable_endpoint pathways to reflect this difference.  This patch adds
corresponding arguments to the disable_endpoint pathways.  Without
this change, the endpoint toggle state can get out of sync between
the host and the device.  The exact mechanism depends on the details
of the host controller (whether or not it stores its own copy of the
toggle values).

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Dan Streetman <ddstreet@ieee.org>
Tested-by: Dan Streetman <ddstreet@ieee.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 24 insertions, 16 deletions

diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index de51667dd64..31fb204f44c 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -1039,14 +1039,15 @@ static void remove_intf_ep_devs(struct usb_interface *intf)
  * @dev: the device whose endpoint is being disabled
  * @epaddr: the endpoint's address.  Endpoint number for output,
  *      endpoint number + USB_DIR_IN for input
+ * @reset_hardware: flag to erase any endpoint state stored in the
+ *      controller hardware
  *
- * Deallocates hcd/hardware state for this endpoint ... and nukes all
- * pending urbs.
- *
- * If the HCD hasn't registered a disable() function, this sets the
- * endpoint's maxpacket size to 0 to prevent further submissions.
+ * Disables the endpoint for URB submission and nukes all pending URBs.
+ * If @reset_hardware is set then also deallocates hcd/hardware state
+ * for the endpoint.
  */
-void usb_disable_endpoint(struct usb_device *dev, unsigned int epaddr)
+void usb_disable_endpoint(struct usb_device *dev, unsigned int epaddr,
+                bool reset_hardware)
 {
         unsigned int epnum = epaddr & USB_ENDPOINT_NUMBER_MASK;
         struct usb_host_endpoint *ep;
@@ -1056,15 +1057,18 @@ void usb_disable_endpoint(struct usb_device *dev, unsigned int epaddr)
 
         if (usb_endpoint_out(epaddr)) {
                 ep = dev->ep_out[epnum];
-                dev->ep_out[epnum] = NULL;
+                if (reset_hardware)
+                        dev->ep_out[epnum] = NULL;
         } else {
                 ep = dev->ep_in[epnum];
-                dev->ep_in[epnum] = NULL;
+                if (reset_hardware)
+                        dev->ep_in[epnum] = NULL;
         }
         if (ep) {
                 ep->enabled = 0;
                 usb_hcd_flush_endpoint(dev, ep);
-                usb_hcd_disable_endpoint(dev, ep);
+                if (reset_hardware)
+                        usb_hcd_disable_endpoint(dev, ep);
         }
 }
 
@@ -1072,17 +1076,21 @@ void usb_disable_endpoint(struct usb_device *dev, unsigned int epaddr)
  * usb_disable_interface -- Disable all endpoints for an interface
  * @dev: the device whose interface is being disabled
  * @intf: pointer to the interface descriptor
+ * @reset_hardware: flag to erase any endpoint state stored in the
+ *      controller hardware
  *
  * Disables all the endpoints for the interface's current altsetting.
  */
-void usb_disable_interface(struct usb_device *dev, struct usb_interface *intf)
+void usb_disable_interface(struct usb_device *dev, struct usb_interface *intf,
+                bool reset_hardware)
 {
         struct usb_host_interface *alt = intf->cur_altsetting;
         int i;
 
         for (i = 0; i < alt->desc.bNumEndpoints; ++i) {
                 usb_disable_endpoint(dev,
-                                alt->endpoint[i].desc.bEndpointAddress);
+                                alt->endpoint[i].desc.bEndpointAddress,
+                                reset_hardware);
         }
 }
 
@@ -1103,8 +1111,8 @@ void usb_disable_device(struct usb_device *dev, int skip_ep0)
         dev_dbg(&dev->dev, "%s nuking %s URBs\n", __func__,
                 skip_ep0 ? "non-ep0" : "all");
         for (i = skip_ep0; i < 16; ++i) {
-                usb_disable_endpoint(dev, i);
-                usb_disable_endpoint(dev, i + USB_DIR_IN);
+                usb_disable_endpoint(dev, i, true);
+                usb_disable_endpoint(dev, i + USB_DIR_IN, true);
         }
         dev->toggle[0] = dev->toggle[1] = 0;
 
@@ -1274,7 +1282,7 @@ int usb_set_interface(struct usb_device *dev, int interface, int alternate)
                 remove_intf_ep_devs(iface);
                 usb_remove_sysfs_intf_files(iface);
         }
-        usb_disable_interface(dev, iface);
+        usb_disable_interface(dev, iface, true);
 
         iface->cur_altsetting = alt;
 
@@ -1353,8 +1361,8 @@ int usb_reset_configuration(struct usb_device *dev)
          */
 
         for (i = 1; i < 16; ++i) {
-                usb_disable_endpoint(dev, i);
-                usb_disable_endpoint(dev, i + USB_DIR_IN);
+                usb_disable_endpoint(dev, i, true);
+                usb_disable_endpoint(dev, i + USB_DIR_IN, true);
         }
 
         config = dev->actconfig;