[linux-dvb] szap for multiproto

Daniel Golle daniel.golle at gmail.com
Tue Jan 29 04:15:22 CET 2008


Once again I'm trying to get my Pinnacle PCTV HD 452e to work (properly)
under Linux. Suspecting there is something wrong with the FEC (as there
are many MPEG errors), I found this line in my kern.log:
newfec_to_oldfec: Unsupported FEC 9
Which is quite surprising, because according to frontend.h DVBFE_FEC can
only contain values which are an integer power of 2.
I found that in in szap.c, line 260 (as well as 266 and 272),
fe_params.delsys.*.fec is set to FEC_AUTO which imho corresponds to the
old api's definition. It should rather be DVBFE_FEC_AUTO.
Also, I'm confused by this newapi_to_olddrv call. I'm using a
(multiproto-ready) szap tool with my (new, stb0899-based) pctv452e.
can't see anything old there....?

Anyway, replacing FEC_AUTO by DVBFE_FEC_AUTO it makes the error in
kern.log go away, but the problem itself persists. I played a little
with the fe_params.delsys.*.fec value in szap.c and discovered that most
values result in the quality of the MPEG to be just the same as before,
some make it a little worse. (I tried all: DVBFE_FEC_NONE,
DVBFE_FEC_1_2, DVBFE_FEC_2_3, ..., DVBFE_FEC_AUTO)

As things work well under windows (inside a virtual machine, the only
way to watch tv for now), I used dvbsnoop inside the vm to get the real
values of the registers of the PCTV using the parser tool posted by
garlicdevel. The actual values of VTH*, FECM and FECAUTO actually look
quite different from those I see in pctv452e.c and also in my kern.log.
Changing them to the ones from the windows driver, however, makes things
worse and tuning fails (NOCARRIER) entirely... So either this parser
tool doesn't work as good as it should or the windows driver really does
things completely different. I'm lost :(

Anyway, can somebody please check this FEC_AUTO <-> DEVFE_FEC_AUTO
confusion in szap (http://abraham.manu.googlepages.com/szap.c)?

Regards

Daniel




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