summaryrefslogtreecommitdiffstats
path: root/drivers/usb/core/hcd.h
diff options
context:
space:
mode:
authorAlan Stern <stern@rowland.harvard.edu>2007-10-10 16:27:07 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2007-10-12 14:55:34 -0700
commit32fe01985aa2cb2562f6fc171e526e279abe10db (patch)
tree0c1865a1d3e91ae0839147430480c4099b16a06f /drivers/usb/core/hcd.h
parent17f060224fb9f435c6f9306b7b61419d038def13 (diff)
downloadblackbird-op-linux-32fe01985aa2cb2562f6fc171e526e279abe10db.tar.gz
blackbird-op-linux-32fe01985aa2cb2562f6fc171e526e279abe10db.zip
USB: mutual exclusion for EHCI init and port resets
This patch (as999) fixes a problem that sometimes shows up when host controller driver modules are loaded in the wrong order. If ehci-hcd happens to initialize an EHCI controller while the companion OHCI or UHCI controller is in the middle of a port reset, the reset can fail and the companion may get very confused. The patch adds an rw-semaphore and uses it to keep EHCI initialization and port resets mutually exclusive. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Acked-by: David Brownell <david-b@pacbell.net> Cc: David Miller <davem@davemloft.net> Cc: Dely L Sy <dely.l.sy@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/core/hcd.h')
-rw-r--r--drivers/usb/core/hcd.h8
1 files changed, 7 insertions, 1 deletions
diff --git a/drivers/usb/core/hcd.h b/drivers/usb/core/hcd.h
index 1396141274f1..98e24194a4ab 100644
--- a/drivers/usb/core/hcd.h
+++ b/drivers/usb/core/hcd.h
@@ -19,6 +19,8 @@
#ifdef __KERNEL__
+#include <linux/rwsem.h>
+
/* This file contains declarations of usbcore internals that are mostly
* used or exposed by Host Controller Drivers.
*/
@@ -470,5 +472,9 @@ static inline void usbmon_urb_complete(struct usb_bus *bus, struct urb *urb,
: (in_interrupt () ? "in_interrupt" : "can sleep"))
-#endif /* __KERNEL__ */
+/* This rwsem is for use only by the hub driver and ehci-hcd.
+ * Nobody else should touch it.
+ */
+extern struct rw_semaphore ehci_cf_port_reset_rwsem;
+#endif /* __KERNEL__ */
OpenPOWER on IntegriCloud