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-rw-r--r--drivers/usb/core/message.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index 228672f2c4a1..bfa5eda0cc26 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -1341,6 +1341,11 @@ void usb_enable_interface(struct usb_device *dev,
* is submitted that needs that bandwidth. Some other operating systems
* allocate bandwidth early, when a configuration is chosen.
*
+ * xHCI reserves bandwidth and configures the alternate setting in
+ * usb_hcd_alloc_bandwidth(). If it fails the original interface altsetting
+ * may be disabled. Drivers cannot rely on any particular alternate
+ * setting being in effect after a failure.
+ *
* This call is synchronous, and may not be used in an interrupt context.
* Also, drivers must not change altsettings while urbs are scheduled for
* endpoints in that interface; all such urbs must first be completed
@@ -1376,6 +1381,12 @@ int usb_set_interface(struct usb_device *dev, int interface, int alternate)
alternate);
return -EINVAL;
}
+ /*
+ * usb3 hosts configure the interface in usb_hcd_alloc_bandwidth,
+ * including freeing dropped endpoint ring buffers.
+ * Make sure the interface endpoints are flushed before that
+ */
+ usb_disable_interface(dev, iface, false);
/* Make sure we have enough bandwidth for this alternate interface.
* Remove the current alt setting and add the new alt setting.
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