uhci_hcd fails to off-line device/hub on error condition

["Michael S. Zick" <lkml@morethan.org>]

On Wed July 8 2009, Michael S. Zick wrote:
> On Wed July 8 2009, Michael S. Zick wrote:
> > On Wed July 8 2009, Michael S. Zick wrote:
> > > On Tue July 7 2009, Alan Stern wrote:
> > > > On Tue, 7 Jul 2009, Michael S. Zick wrote:
> > > > 
> > > > > On Tue July 7 2009, Alan Stern wrote:
> > > > > > On Tue, 7 Jul 2009, Michael S. Zick wrote:
> > > > > > 
> > > > > > > > It looks like there's a serious problem in your UHCI hardware.  
> > > > > > > > According to the log you posted, it's not working at all.
> > > > > > > > 
> > > > > > > 
> > > > > > > I am using the x86-generic drivers - -
> > > > > > 
> > > > > > Not a problem with the drivers, a problem in the hardware.
> > > > > > 
> > > > > 
> > > > > Or hardware that works as the manufacturer intended, but differently
> > > > > than expected.  Same difference as "broken" when compared to "standard".
> > > > 
> > > > No, hardware that doesn't work at all.  As in "all reads return
> > > > 0xffffffff" -- that's just a guess but something like it would account
> > > > for what you saw.
> > > > 
> 
> I tried to combine the addition of the diagnostic print (BUG())
> statements and the potential fix - -
> This is what I put into the code for today's testing:
> 
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index be86ae3..d686f1d 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -160,8 +160,10 @@ static inline char *portspeed(int portstatus)
>  }
> 
>  /* Note that hdev or one of its children must be locked! */
> -static inline struct usb_hub *hdev_to_hub(struct usb_device *hdev)
> +static struct usb_hub *hdev_to_hub(struct usb_device *hdev)
>  {
> +       if (!hdev || !hdev->actconfig)
> +               return NULL;
>         return usb_get_intfdata(hdev->actconfig->interface[0]);
>  }
> 
> @@ -369,11 +371,16 @@ static void kick_khubd(struct usb_hub *hub)
>  {
>         unsigned long   flags;
> 
> -       /* Suppress autosuspend until khubd runs */
> -       to_usb_interface(hub->intfdev)->pm_usage_cnt = 1;
> +       if (!hub) {
> +               BUG();
> +               return;
> +       }
> 
>         spin_lock_irqsave(&hub_event_lock, flags);
>         if (!hub->disconnected && list_empty(&hub->event_list)) {
> +               /* Suppress autosuspend until khubd runs */
> +               to_usb_interface(hub->intfdev)->pm_usage_cnt = 1;
> +
>                 list_add_tail(&hub->event_list, &hub_event_list);
>                 wake_up(&khubd_wait);
>         }
> @@ -382,8 +389,19 @@ static void kick_khubd(struct usb_hub *hub)
> 
>  void usb_kick_khubd(struct usb_device *hdev)
>  {
> -       /* FIXME: What if hdev isn't bound to the hub driver? */
> -       kick_khubd(hdev_to_hub(hdev));
> +       struct usb_hub *hub;
> +
> +       if (!hdev) {
> +               BUG();
> +               return;
> +       }
> +       hub = hdev_to_hub(hdev);
> +       if (hub) {
> +               kick_khubd(hub);
> +       } else {
> +               BUG();
> +               return;
> +       }
>  }
>

- - Megabytes of the same snipped - -
uhci_hcd 0000:00:10.2: host controller process error, something bad happened!
uhci_hcd 0000:00:10.1: host system error, PCI problems?
uhci_hcd 0000:00:10.1: host controller process error, something bad happened!
uhci_hcd 0000:00:10.2: host system error, PCI problems?
uhci_hcd 0000:00:10.2: host controller process error, something bad happened!

- - driver can detect unexpected behavior sufficent to post the messages - -

uhci_hcd 0000:00:10.1: host system error, PCI problems?
uhci_hcd 0000:00:10.1: host controller process error, something bad happened!

- - but never does anything about it - other than bitch - -
- - insert external action: rmmod uhci_hcd here - -

uhci_hcd 0000:00:10.2: remove, state 1
uhci_hcd 0000:00:10.2: roothub graceful disconnect
usb usb4: USB disconnect, address 1
usb usb4: unregistering device
usb usb4: usb_disable_device nuking all URBs
usb usb4: unregistering interface 4-0:1.0
uhci_hcd 0000:00:10.2: host system error, PCI problems?
uhci_hcd 0000:00:10.2: host controller process error, something bad happened!
uhci_hcd 0000:00:10.1: host system error, PCI problems?
uhci_hcd 0000:00:10.1: host controller process error, something bad happened!
uhci_hcd 0000:00:10.1: host system error, PCI problems?
uhci_hcd 0000:00:10.1: host controller process error, something bad happened!
uhci_hcd 0000:00:10.2: host system error, PCI problems?
uhci_hcd 0000:00:10.2: host controller process error, something bad happened!
uhci_hcd 0000:00:10.1: host system error, PCI problems?
uhci_hcd 0000:00:10.1: host controller process error, something bad happened!
uhci_hcd 0000:00:10.2: host system error, PCI problems?
uhci_hcd 0000:00:10.2: host controller process error, something bad happened!
uhci_hcd 0000:00:10.1: host system error, PCI problems?
uhci_hcd 0000:00:10.1: host controller process error, something bad happened!
uhci_hcd 0000:00:10.2: host system error, PCI problems?
uhci_hcd 0000:00:10.2: host controller process error, something bad happened!
uhci_hcd 0000:00:10.1: host system error, PCI problems?
uhci_hcd 0000:00:10.1: host controller process error, something bad happened!
usb 4-0:1.0: uevent
usb usb4: uevent
uhci_hcd 0000:00:10.2: USB bus 4 deregistered
uhci_hcd 0000:00:10.1: remove, state 1
uhci_hcd 0000:00:10.1: roothub graceful disconnect
usb usb3: USB disconnect, address 1
usb usb3: unregistering device
usb usb3: usb_disable_device nuking all URBs
usb usb3: unregistering interface 3-0:1.0
usb 3-0:1.0: uevent
usb usb3: uevent
uhci_hcd 0000:00:10.1: USB bus 3 deregistered
uhci_hcd 0000:00:10.0: remove, state 0
uhci_hcd 0000:00:10.0: roothub graceful disconnect
usb usb2: USB disconnect, address 1
usb usb2: unregistering device
usb usb2: usb_disable_device nuking all URBs
usb usb2: unregistering interface 2-0:1.0
usb 2-0:1.0: uevent
usb usb2: uevent
uhci_hcd 0000:00:10.0: USB bus 2 deregistered
 
- - end event - - (with apologies to China Syndrome)

Mike
> Mike
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