On Sat, 13 February 2010 Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
>
> On Sat, 13 Feb 2010, Bruno [UTF-8] Prémont wrote:
>
> > On Mon, 08 February 2010 Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
> > wrote:
> > > Clearly something is setting usbhid->intf to NULL. But I don't
> > > see any code that would do it. You may have to resort to putting
> > > printk() statements at various strategic places to find out where
> > > it happens. You could start with the beginnings and ends of
> > > hid_suspend, hid_resume, and hid_reset_resume. Maybe also
> > > usbhid_disconnect(), just in case.
> >
> > I did add a few printk()s and WARN_ON()s to get a better idea of
> > why/when usbhid->intf is NULL and it is already since probe time of
> > the second interface anounced by the USB keyboard (hid.debug=1):
>
> ...
>
> > This lets me guess that hid_add_device() is doing something wrong
> > here when report parsing fails... (as that one is the only one which
> > could be doing the initialization of usbhid which does work for the
> > first interface announced by my keyboard)
>
> I don't know about doing anything wrong... However it does appear
> that in this case the interface is registered on the HID bus but
> doesn't get bound to a driver. Jiri will know whether or not that's
> the desired outcome.
>
> On the other hand, I don't think there would be anything wrong with
> moving the
>
> usbhid->intf = intf;
> usbhid->ifnum = interface->desc.bInterfaceNumber;
>
> lines from usbhid_start() to usbhid_probe(), just before the call to
> hid_add_device(). It should fix the bug, and those lines do belong in
> the probe routine. Jiri, any problems with doing this?
With the below patch (which is only half of the move work) I don't
get crashes anymore. Though I wonder if other initialization steps
(like the spin_lock_init() right before setting usbhid->intf) would
need to be moved as well.
Bruno
diff --git a/drivers/hid/usbhid/hid-core.c b/drivers/hid/usbhid/hid-core.c
index e2997a8..690ca75 100644
--- a/drivers/hid/usbhid/hid-core.c
+++ b/drivers/hid/usbhid/hid-core.c
@@ -1154,6 +1154,8 @@ static int usbhid_probe(struct usb_interface *intf, const struct usb_device_id *
hid->driver_data = usbhid;
usbhid->hid = hid;
+ usbhid->intf = intf;
+ usbhid->ifnum = interface->desc.bInterfaceNumber;
ret = hid_add_device(hid);
if (ret) {
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