diff options
| author | Takamasa Ohtake <ohtake-txa@necst.nec.co.jp> | 2006-12-06 17:04:15 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2006-12-20 10:14:27 -0800 |
| commit | 23d10a9e376d6a9cd4afd4e27e5e403864f6729b (patch) | |
| tree | ed13d347496c39fc25a0688385b83e1f0b17a302 /drivers/usb | |
| parent | ee269d98a9248fbb729c20ffda0f1b97e82c5c37 (diff) | |
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 <ohtake-txa@necst.nec.co.jp>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb')
| -rw-r--r-- | 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 f9748b67e5e..216c9c9d4d6 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; |