[linux-dvb] Re: [Patch] USBVision - Fix NT1005 Bridge detection

Mauro Carvalho Chehab mchehab at infradead.org
Sat Apr 14 20:29:53 CEST 2007

Hi Thierry,

> I am currently debugging the Trent's patch that makes a kernel oops and 
> I don't know why.
> The usbvision_probe is called event if the device is not plugged, and 
> the kernel oops occurs on this piece of code:
>     model = devid->driver_info;
>     printk(KERN_INFO "%s: %s found\n", __FUNCTION__,
>                 usbvision_device_data[model].ModelString);
> Memory alignment problem ? Why this probe is called even if there is no 
> device plugged-in ?
Very weird. It shouldn't be called when no device is plugged...

> By putting something like:
>     model = devid->driver_info;
>     if(model<0 || model >HPG_WINTV) {
>         printk(KERN_INFO "model out of bounds %d\n",model);
>         return -ENODEV;
>     } else printk(KERN_INFO "model is %d\n",model);
> The problem disappeared...

A similar code is also present on em28xx. Anyway, it is better to have
this kind of protection. I've added a patch, based on yours, fixing the
bug. As you'd agreed, I've pushed the patches to master tree.

It is better, however, to check why it is calling the code, without a
valid USB ID, since it may mean a future trouble...

Btw, I think we can also apply this one also:

diff -r 6b6805e3c76d linux/drivers/media/video/usbvision/usbvision-video.c
--- a/linux/drivers/media/video/usbvision/usbvision-video.c	Sat Apr 14 15:17:08 2007 -0300
+++ b/linux/drivers/media/video/usbvision/usbvision-video.c	Sat Apr 14 15:19:06 2007 -0300
@@ -1985,8 +1985,6 @@ static int __devinit usbvision_probe(str
 		return -ENODEV;
-	usb_get_dev(dev);
 	if ((usbvision = usbvision_alloc(dev)) == NULL) {
 		err("%s: couldn't allocate USBVision struct", __FUNCTION__);
 		return -ENOMEM;

usb_get_dev() is already called previously on usbvision_probe.


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