[linux-dvb] Re: Strange problem with TT budget DVB-C - tuning ok but no data

[Oliver Endriss <o.endriss@gmx.de>]

emard@softhome.net wrote:
> Current solution is a trial and error solution, run application many
                                                  ^^^^^^^^^^^^^^^^^^^^
> times to open demux and settle when you got it running... bad design
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> but that's the way 7146 is operating

Hm, enabling SAA7146 reset again in saa7146_core.c helped here.

> Failures happen because the BRS initialization code is time-dependent
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> from reset or other conditions of internal saa7146 state that can't
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> be simply predicted if the time since 7146 reset is longer than some 10-20ms,
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> unless we construct a complex rps code that waits for internal events 
> like BRS_DONE, and other and initialize during inactive states of those
> events.

Why? _If_ the reset code correctly disables RPS/DMA etc. there should be
no difference whether you start RPS/DMA after 10ms or after 1 year.

Otherwise the reset code hast to be fixed or the saa7146 is buggy.

> Whatever we choose to do, reset or waiting for events, 
> I'm talking of developing a reliable initialization procedure, 
> that needs to be done just once.

If the chip is really buggy, it would be better to do a _complete_ reset
whenever start_ts_capture() is called and budget->feeding==0.
Robustness is more important than a beautiful design.

I _hate_ drivers which have to be reloaded when unhandled error 
conditions occur.

If you completely remove device setup from start_ts_capture() you will
probably create a driver which has to be reloaded after a failure...

Oliver

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