Hans Verkuil wrote:
OK, I think I've fixed the problem of missing sound on the PVR150/500. Please
update to the latest svn and try again. Besides some bug fixes the main cause
seems to be the initialization of the Delay Lock Loops. If I understand the
datasheet correctly these DLLs are responsible for the timings in the Luma
ADC and the Audio Decoder.
The initialization sequence should ensure that no false lock is detected but
the old sequence in the driver differs substantially from what Hauppauge
does, which in turn is much closer to the recommended procedure from the
datasheet. I suspect that sometimes, possibly depending on all kinds of
environmental factors (e.g. interference), a false lock is detected and the
audio decoder effectively no longer works. I also suspect that the old
sequence was unable to properly force a new attempt to lock, so if was wrong
from the start, it stayed wrong. It also explains why some people could make
it work by first running the Hauppauge driver and then soft boot to linux:
the Hauppauge driver forces the correct DLL which remained correct in linux.
This is interesting because Bryan Mayland pulled those setting out of
the disassembled Windows driver- the exact datasheet method would only
give us sound on every other driver load.
--
Tyler Trafford
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