[linux-dvb] Possible patch for CAM/CI issues

Andrew de Quincey adq_dvb at lidskialf.net
Mon Nov 7 19:13:39 CET 2005

On Monday 07 Nov 2005 18:04, Marco Coli wrote:
> Andrew de Quincey wrote:
> > (resend to list due to stupidity)
> >
> > Hi, this is a first attempt at fixing the remaining CI driver issues.
> >
> > I'm not sure where the problems Macro + Andreas reported are coming from
> > - they could either be from the application or from the driver, but I
> > included you in the CC in case this patch helps...
> >
> > Main features of this patch: slight restructuring in order to remove
> > locking completely - simplifies code and also should increase speed since
> > there is no locking necessary now. Also decreases the amount of work done
> > in IRQ context.
> I tried the patch. All log messages regarding IRQ (present with previous
> version) are gone, so it'a good work :-)

Well thats good to hear! :)

> Unluckily, I have again the strange interruptions on encrypted channels
> (ERROR: CAM: Read failed: slot 0, tcid 1
> [pause 1,2 or 40 seconds, randomly]
> CI resource manager: unexpected data
> CAM: NCAS, 01, 0001, 0001
> I suppose my symptoms are similar (but less blocking, from description)
> to those reported from irk:
> > I have two CAM's, one is called Matrix Revolutions, another is called
> > X-CAM. These are CAM's which can be used with multiple encryption
> > systems. I tested them with SECA Mediaguard. What happens is that X-CAM
> > works perfectly but Matrix has big troubles. Lots of squares appear in
> > the picture and driver complains about CRC errors. Both CAM's work
> > perfectly in quite old set-top box.
> My cam is also a Matrix Revolution, NCAS programmed. I don't know where
> the problem could be...

Hmm, the pause (and likely blocking) will be because the driver/application 
thinks it has lost communications with the CAM, so it has reset it, and 
restarts the negotiation protocol to start the decryption. During this time, 
obviously, no decryption will occur.

I wonder if it is actually losing the data, or if its just being slow for some 
reason... e.g the "CI resource manager: unexpected data" bit might imply it 
did get something, but after a delay. Since irk reported his other CAM works 
perfectly, its _probably_ not a machine load issue affecting the comms with 
the CAM.

I'll have a quick look into the driver reading code. Although I think that 
error is being reported by the userspace application (VDR?) - but that 
doesn't mean VDR is causing the error - just reporting it.

Does anyone with a full featured card +CI module have one of these CAMs they 
can try? 

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