Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=23d10a9e376d6a9cd4afd4e27e5e403864f6729b
Commit: 23d10a9e376d6a9cd4afd4e27e5e403864f6729b
Parent: ee269d98a9248fbb729c20ffda0f1b97e82c5c37
Author: Takamasa Ohtake <[EMAIL PROTECTED]>
AuthorDate: Wed Dec 6 17:04:15 2006 -0800
Committer: Greg Kroah-Hartman <[EMAIL PROTECTED]>
CommitDate: Wed Dec 20 10:14:27 2006 -0800
USB: ohci handles hardware faults during root port resets
I have found a problem where the root_port_reset() goes into an infinite
loop and stalls the kernel.
This happens when a hardware fault inside the machine occurs during a small
timing window. In case of USB device connection, if a USB device responds
to
hcd_submit_urb(), and later the controller fails before root_port_reset(),
root_port_reset() will loop infinitely because ohci_readl() will always
return "-1". Such a failure can include ejecting a CardBus OHCI controller.
The probability of this problem is low, but it will increase if PnP type
usage is frequent. The attached patch can solve this problem and I believe
that it is better to fix this problem.
Signed-off-by: Takamasa Ohtake <[EMAIL PROTECTED]>
Signed-off-by: David Brownell <[EMAIL PROTECTED]>
Signed-off-by: Greg Kroah-Hartman <[EMAIL PROTECTED]>
---
drivers/usb/host/ohci-hub.c | 9 +++++++--
1 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/host/ohci-hub.c b/drivers/usb/host/ohci-hub.c
index f9748b6..216c9c9 100644
--- a/drivers/usb/host/ohci-hub.c
+++ b/drivers/usb/host/ohci-hub.c
@@ -555,7 +555,7 @@ static void start_hnp(struct ohci_hcd *ohci);
#define tick_before(t1,t2) ((s16)(((s16)(t1))-((s16)(t2))) < 0)
/* called from some task, normally khubd */
-static inline void root_port_reset (struct ohci_hcd *ohci, unsigned port)
+static inline int root_port_reset (struct ohci_hcd *ohci, unsigned port)
{
__hc32 __iomem *portstat = &ohci->regs->roothub.portstatus [port];
u32 temp;
@@ -570,6 +570,9 @@ static inline void root_port_reset (struct ohci_hcd *ohci,
unsigned port)
/* spin until any current reset finishes */
for (;;) {
temp = ohci_readl (ohci, portstat);
+ /* handle e.g. CardBus eject */
+ if (temp == ~(u32)0)
+ return -ESHUTDOWN;
if (!(temp & RH_PS_PRS))
break;
udelay (500);
@@ -586,6 +589,8 @@ static inline void root_port_reset (struct ohci_hcd *ohci,
unsigned port)
now = ohci_readl(ohci, &ohci->regs->fmnumber);
} while (tick_before(now, reset_done));
/* caller synchronizes using PRSC */
+
+ return 0;
}
static int ohci_hub_control (
@@ -702,7 +707,7 @@ static int ohci_hub_control (
&ohci->regs->roothub.portstatus [wIndex]);
break;
case USB_PORT_FEAT_RESET:
- root_port_reset (ohci, wIndex);
+ retval = root_port_reset (ohci, wIndex);
break;
default:
goto error;
-
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