[linux-dvb] Re: Busy waiting in i2c_busy_rise_and_fall (was: Re: Re: full featured card without signal and required video memory investigation)

["Robert Schlabbach" <robert_s@gmx.net>]

From: "Marcus Metzler" <mocm@metzlerbros.de>
> It seems that the additional usage of the i2c bus by the checking
> calls somehow results in a loss of lock or maybe just a faulty
> return value.

Hmm, I know of at least one tuner module for which the data sheet says that
you must not use the I2C bus for at least 60 microseconds after programming
the PLL, or the tuning will fail. Maybe there are other frontend components
which are equally sensitive to I2C traffic right after being programmed? If
so, that'd be a bug in the corresponding frontend module, which must
include a delay call for the required minimum "silence" period on the I2C
bus...

IMHO, each module should ensure stable operation in itself. No sequence of
calls to frontend functions should ever lead to reception problems. I'd say
do not fix your calls, but rather identify the buggy frontend modules and
fix those...

Regards,
--
Robert Schlabbach
e-mail: robert_s@gmx.net
Berlin, Germany



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