[linux-dvb] High BER's & Glitching with 2.6 kernel, better with 2.4 and 1.0.0-pre2(Nova-T)

[Dave Smith <dave@nobodynet.net>]

Hello,

I've posted about this problem before, but have never had an answer.  
Sorry for the re-post (I know how annoying re-posters can be), but I have just 
tried the driver with the 2.6.2 kernel today, and I still have the same problem.

Basically, when using my NOVA-T card with the 2.6 kernel driver (or with 
2.4 and any version of the driver from 1.0.0-pre3 and upwards) I get a LOT 
more digital breakup/glitches, etc. than I did with the driver I was 
previously using, 1.0.0-pre2.  The stream from the card is unusable with 
the newer drivers.

Just to give you some numbers, when looking at the same mux (BBC Mux 1) from 
Crystal Palace, with pre2 I get typical readings of:

snr e6e6 | ber 000000ea | unc 00000000 
snr e5e5 | ber 000000e8 | unc 00000000 
snr e5e5 | ber 000000e5 | unc 00000000 

....I do get the occasional UNConcealed error, but only a couple over, 
say, half an hour.

Using drivers 1.0.0-pre3 up to 1.0.1, and with the kernel 2.6 drivers, I  
get typical readings of:

snr e5e5 | ber 00000158 | unc 0000000f 
snr e5e5 | ber 00000149 | unc 0000000d 
snr e5e5 | ber 00000139 | unc 0000000d 
snr e3e3 | ber 00000166 | unc 00000020 
snr d5d5 | ber 000000e8 | unc 0000000a

i.e the SNR fluctuates more, the BER is generally higher, and I get a 
large number of unconcealed errors.  The resulting stream is pretty much 
un-decodable.

The above readings were taken within 10 minutes of each other, with the 
only change being the driver version loaded.

I'm using a NOVA-T card (grundig_29504-401/saa7146), and a 
2.4.20 kernel or 2.6.2 kernel for testing.

The last time I posted about this, someone suggested that I go through the 
CVS between pre2 and pre3 and find out what date the error appears.  I haven't 
done this, mainly because I'm not adept enough at using CVS (my "coding" 
skills don't go much beyond scripts), but if someone thinks this is a good 
approach, and want's to post some breif instructions on how I pull 
specific dates from the cvs, then I'll give that a go.

Please can someone give me some pointers.  This problem is stopping me 
from moving over to a 2.6 kernel.

Cheers,
--Dave






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