[linux-dvb] Re: dvb-kernel doesn't initialize secondary card

[Ralph Metzler <rjkm@metzlerbros.de>]

Hi, 

I always thought this "no return from standby problem" only occurs on 
cards with SU1278/SHA. On KNC and Hauppauge cards (at least on mine) 
this problem was not so bad.

Robert Schlabbach writes:
 > From: "Oliver Endriss" <o.endriss@gmx.de>
 > > Update:
 > > | Sep 26 00:52:01 orion kernel: uni0299_attach: id == 0x00
 > > Obviously, the id register of the stv0299 cannot be read in standby
 > > mode!

The driver you use seems to check for other IDs but not for 0x00 and then 
tries to wake up the STV0299. I use code which first tries to detect the
STV0299 twice (sometimes it was not detected at all at the first try),
then it tries to get out of standby no matter which ID it found and
then checks the ID again. But since even this procedure does not work 
with all cards I do not go to standby mode anymore. 

Even if this depends on the SAA7146 I2C driver version (a timing
issue?) I would not recommend using it anymore because the problem
also occured on other I2C hosts (e.g. SAA7134) and can cause a lot of pain ...


 > That's true. According to the STV0299B datasheet, only registers 0x01, 0x02
 > and 0x03 are accessible in standby mode.
 > 
 > I haven't looked at the code, but shouldn't a proper standby mode also
 > include setting the SAA7146A's GPIO pin 2 to LOW? AFAIK, that pin is used
 > to power down (or reset) the frontend on all TechnoTrend-designed cards. If
 > you set that pin to low and then to high again, the STV0299B will _not_ be
 > in standby mode and can be properly detected.

The problem is with frontend sleeping not a general standby. GPIO 2
only works with the full feature cards and would also put the AV7110
into reset. On non-TT cards the GPIO ports can have very different functions.
Older KNC card versions cannot reset the STV0299 at all.

Anyway, I think for most setups switching off frontend power is the most
important part. The STV0299 itself should not use that much power. For
low power STBs this could of course be relevant. 



Ralph


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