diff options
| author | Alan Stern <stern@rowland.harvard.edu> | 2007-10-12 15:19:14 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2007-11-21 09:25:56 -0800 |
| commit | 0afc57fe16f55c446f7d421f84e3c7cf0a938777 (patch) | |
| tree | db7dcc2f8bea7e223f358c6a8cbc978e413e2341 /drivers/usb/core/hub.c | |
| parent | 12a245310134c88936581be7be9d08afc847120f (diff) | |
USB: mutual exclusion for EHCI init and port resets
patch 32fe01985aa2cb2562f6fc171e526e279abe10db in mainline.
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/hub.c')
| -rw-r--r-- | drivers/usb/core/hub.c | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index a1c1a11dd9b..bc93e061cdc 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -117,6 +117,12 @@ MODULE_PARM_DESC(use_both_schemes, "try the other device initialization scheme if the " "first one fails"); +/* Mutual exclusion for EHCI CF initialization. This interferes with + * port reset on some companion controllers. + */ +DECLARE_RWSEM(ehci_cf_port_reset_rwsem); +EXPORT_SYMBOL_GPL(ehci_cf_port_reset_rwsem); + static inline char *portspeed(int portstatus) { @@ -1513,6 +1519,11 @@ static int hub_port_reset(struct usb_hub *hub, int port1, { int i, status; + /* Block EHCI CF initialization during the port reset. + * Some companion controllers don't like it when they mix. + */ + down_read(&ehci_cf_port_reset_rwsem); + /* Reset the port */ for (i = 0; i < PORT_RESET_TRIES; i++) { status = set_port_feature(hub->hdev, @@ -1543,7 +1554,7 @@ static int hub_port_reset(struct usb_hub *hub, int port1, usb_set_device_state(udev, status ? USB_STATE_NOTATTACHED : USB_STATE_DEFAULT); - return status; + goto done; } dev_dbg (hub->intfdev, @@ -1556,6 +1567,8 @@ static int hub_port_reset(struct usb_hub *hub, int port1, "Cannot enable port %i. Maybe the USB cable is bad?\n", port1); + done: + up_read(&ehci_cf_port_reset_rwsem); return status; } |