[vdr] Re: Can vdr work without antenna? (play recordings)

[Gregor Lawatscheck <gpel@mpex.net>]

Dennis Noordsij wrote:

> Well analysing all driver<->firmware communications in the 0.9.4 and the 
> dvb-kernel driver is possible, but the firmware itself was also different, so 
> if it reacts differently or the API is very different then it gets difficult 
> to see what is going on.
Exactly. I was never quite sure whether this is in the firmware or the 
driver. Best guess might still be the firmware now that it turns out 
unloading the front-end doesn't resolve it. To get this straight: You 
have one rev 1.3. that is stable in replay-only mode with new drivers 
and new firmware even with the front-end loaded or does the frontend 
have to be unloaded for the stable 1.3? The other question is whether 
the crashy card is in fact stable with a signal and new drivers - just 
to make sure the card isn't broken in some other way.

> There was an interesting thread on the DVB list of using the old firmware with 
> the newer drivers.
Yes, the problem with that is, because of unsupported features the old 
firmware it tends to crash the ARM with newer drivers for different 
reasons. Trying the old firmware with the new drivers without using 
advanced features might be a good test.

> By the way, what seems to trigger it? 
Starting and stopping replay seems to provoke the crash more easily. 
Heavy channel changing will crash it within half an hour or shorter. 
Replaying a live stream might work for hours but will eventually crash 
as well - even if vdr is told not to tune to other transponders to fetch 
EPG data.

It looks as though some check to tune fails somewhere internally or 
isn't caught before timing out. It seems as though most of the time it 
returns some value that it can't tune, the driver / firmware is OK with 
it. Sometimes it might not return something in quite a while or hang 
itself up in the process - if that happens it crashes. At that point 
what can the driver / firmware do... hard reset the card I guess. It's 
trying that, but it fails. Now replaying with mplayer doesn't tune to a 
channel - yet it can be used to crash the ARM with continuous replaying. 
So something in the newer drivers or firmware might check to tune to 
channel and didn't do so in the earlier versions...

> If one were to make a VDR output plugin 
> which always sends valid data to the DVB device, instead of letting VDR use 
> the device directly, could that solve things?
I don't think it's because of invalid data - that yet again a different 
issue. The ARM can be made to crash on screwed up data but even newer 
revisions have that problem afaik.


- Gregor


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