On Tue, 9 Oct 2007, Greg KH wrote:
> > Anyway, it certainly would be easy enough to make port resets mutually
> > exclusive with EHCI initialization. That would work on any platform,
> > PCI or not.
>
> That's a good idea, any thoughts as to how to do this? I think I can
> find some Intel and Dell people who would be glad to test this out if
> you have a proposed patch.
Here is a proposed patch. I haven't tried running it, but it compiles
okay.
Alan Stern
Index: usb-2.6/drivers/usb/core/hcd.h
===================================================================
--- usb-2.6.orig/drivers/usb/core/hcd.h
+++ usb-2.6/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(s
: (in_interrupt () ? "in_interrupt" : "can sleep"))
-#endif /* __KERNEL__ */
+/* Mutual exclusion for EHCI CF initialization. This interferes with
+ * port reset on some companion controllers.
+ */
+extern struct rw_semaphore ehci_cf_port_reset_rwsem;
+#endif /* __KERNEL__ */
Index: usb-2.6/drivers/usb/core/hub.c
===================================================================
--- usb-2.6.orig/drivers/usb/core/hub.c
+++ usb-2.6/drivers/usb/core/hub.c
@@ -125,6 +125,12 @@ 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)
{
@@ -1579,6 +1585,8 @@ static int hub_port_reset(struct usb_hub
{
int i, status;
+ down_read(&ehci_cf_port_reset_rwsem);
+
/* Reset the port */
for (i = 0; i < PORT_RESET_TRIES; i++) {
status = set_port_feature(hub->hdev,
@@ -1610,7 +1618,7 @@ static int hub_port_reset(struct usb_hub
usb_set_device_state(udev, status
? USB_STATE_NOTATTACHED
: USB_STATE_DEFAULT);
- return status;
+ goto done;
}
dev_dbg (hub->intfdev,
@@ -1623,6 +1631,8 @@ static int hub_port_reset(struct usb_hub
"Cannot enable port %i. Maybe the USB cable is bad?\n",
port1);
+ done:
+ up_read(&ehci_cf_port_reset_rwsem);
return status;
}
Index: usb-2.6/drivers/usb/host/ehci-hcd.c
===================================================================
--- usb-2.6.orig/drivers/usb/host/ehci-hcd.c
+++ usb-2.6/drivers/usb/host/ehci-hcd.c
@@ -646,9 +646,11 @@ static int ehci_run (struct usb_hcd *hcd
* involved with the root hub. (Except where one is integrated,
* and there's no companion controller unless maybe for USB OTG.)
*/
+ down_write(&ehci_cf_port_reset_rwsem);
hcd->state = HC_STATE_RUNNING;
ehci_writel(ehci, FLAG_CF, &ehci->regs->configured_flag);
ehci_readl(ehci, &ehci->regs->command); /* unblock posted writes */
+ up_write(&ehci_cf_port_reset_rwsem);
temp = HC_VERSION(ehci_readl(ehci, &ehci->caps->hc_capbase));
ehci_info (ehci,
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