[linux-dvb] Freecom DVB-T USB Stick Kernel OOps

[Patrick Boettcher]

Hi,

On Thu, 29 Dec 2005, rbnw07377 at blueyonder.co.uk wrote:
> Received the following kernel oops whilst using scandvb on:
>> uname -a
> Linux laptop 2.6.14-1.1644_FC4 #1 Sun Nov 27 03:25:11 EST 2005 i686 i686
> i386 GNU/Linux
> (Dell Latitude C600)
>
> Sorry about the size, but I'm not sure which of this lot is important!!!
> This happens everytime I use scandvb or when scanning using Kaffeine
> (which I think is the same thing :-)).  Sometimes the whole lot just
> freezes and I have to hard reboot.

Yes!! Finally I see what the problem is people pointing out all the time 
in previous threads:
Eg.: http://www.linuxtv.org/pipermail/linux-dvb/2005-December/006853.html

and other threads (such as Twinhan Alpha Twincard).

Those cards in running mode exceed the USB power specification 
(500mA/device) and that's why:

> Dec 28 00:56:39 localhost kernel: dvb-usb: bulk message failed: -71 (1/1)
> Dec 28 00:56:40 localhost kernel: hub 1-0:1.0: port 1 disabled by hub
> (EMI?), re-enabling...
> Dec 28 00:56:40 localhost kernel: usb 1-1: USB disconnect, address 3

And unfortunately the dvb-usb (or rather the dvb-core) is not capable of 
hotplug-events and that's why:

> Dec 28 00:56:40 localhost kernel: Unable to handle kernel paging request
> at virtual address d4b0a2a4
> Dec 28 00:56:40 localhost kernel: EIP is at dvb_demux_poll+0x28/0x61
> [dvb_core]

Because the unplug caused the driver to deallocate the dvb-structures 
while the device is used by an application.

> Dec 28 00:56:41 localhost kernel: usb 1-1: new full speed USB device using
> uhci_hcd and address 4
> Dec 28 00:56:41 localhost kernel: dvb-usb: found a 'WideView WT-220U
> PenType Receiver (Typhoon/Freecom)' in warm state.
> Dec 28 00:56:41 localhost kernel: dvb-usb: will use the device's hardware
> PID filter (table count: 15).
> Dec 28 00:56:41 localhost kernel: DVB: registering new adapter (WideView
> WT-220U PenType Receiver (Typhoon/Freecom)).
> Dec 28 00:56:41 localhost kernel: DVB: registering frontend 0 (WideView
> USB DVB-T)...
> Dec 28 00:56:41 localhost kernel: dvb-usb: schedule remote query interval
> to 300 msecs.
> Dec 28 00:56:41 localhost kernel: dvb-usb: WideView WT-220U PenType
> Receiver (Typhoon/Freecom) successfully initialized and connected.
> Dec 28 00:56:42 localhost kernel: dvb-usb: recv bulk message failed: -110

After sometime the USB hub allows the device to show up again. (it is 
still in warm state, that's why there is no firmware download).

Patrick.

--
   Mail: patrick.boettcher at desy.de
   WWW:  http://www.wi-bw.tfh-wildau.de/~pboettch/