Re: [linux-dvb-maintainer] Re: [OOPS] Linux 2.6.14.2 and DVB USB

[Patrick Boettcher <patrick.boettcher@desy.de>]

Hi,

On Tue, 15 Nov 2005, Johannes Stezenbach wrote:
>> Unfortunately the dvb-core is currently not able to handle hotplugging
>> while a dvb application is accessing a dvb-dev-node. This applies
>> for every dvb-device, not only for dvb-usb devices, but no one ever tried
>> to unplug a DVB PCI card while using it, yet.
>>
>> Before unplugging a device, you can check if the module is removable to
>> make sure that really no application is currently using it. (You will get
>> "module in use" then).
>>
>> We already thought about that problem and we think that dvbdev.c is the
>> correct place to start implementing that, but I don't have enough
>> knowledge (and time) to do that now, sorry.
>
> I thought someone sent a patch which fixes it for the cinergyT2
> recently? Wouldn't the same approach work for dvb-usb?
> (But I haven't had a chance to test the cinergyT2 patch yet.)

Once Deti Fliegl created that patch I had a look at it to figure out if it 
can easily be adapted to dvb-usb. This is was my answer:

http://www.linuxtv.org/pipermail/linux-dvb/2005-October/005333.html

After that mail I had some private mails with Deti, but he is currently 
too busy to adapt his mechanism to dvbdev.c and I'm too stupid.

The cinergy-driver handles the frontend in a different way and that's 
why it is possible to fix it like Deti does it.

If I could fix it in in dvb-usb, then it would be again only fixed for a 
small amount of devices. For DVB-PCMCIA-cards using the default 
fe-architecture will also cause Oopses like that, when unplugging while 
having the device in use. That's why, IMHO, the dvb-core should be made 
hotplug-safe, not a single driver. Even worse: it's not just the 
frontend-device-nodes, but also the demux-nodes (and I think the other 
onces too).

best regards,
Patrick.

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