[linux-dvb] Re: [Patch] Adding support for the Hauppage HVR1100

Johannes Stezenbach js at linuxtv.org
Tue Nov 29 18:55:20 CET 2005


On Tue, Nov 29, 2005, Steve Toth wrote:
> Two very different parts of the kernel need to use the same PLL. When 
> you're inside the cx22702 driver it's a no brainer, you can toggle the 
> gate. When you're outside of the 702 driver, in tuner.ko, you have no 
> concept of the 702, you only have an I2C bus to operate on. I could not 
> see a nice solution to the problem without a lot of re-engineering.of 
> the kernel tuner support in V4L.
> 
> Please, I'm open to ideas.

In the DVB drivers, the PLL is not directly accessed by the
demod driver. It is done by the card driver.

I.e. the cx88 driver knows from the PCI ids and eeprom
that the PLL is behind the cx22702 i2c gate. So it could
do the right thing.

But I assume the tuner.ko design makes this more difficult?
I don't have much knowledge about analog, but can the cx88
driver not hook the v4l ioctl and open the gate before
calling into tuner.ko?

> Question: In it's current form (1) will you accept the patch? If not, we 
> need to come to a consensus on the best approach and begin implementation.

I would like to discuss and try to find a better way first. If we cannot
come up with a simple and good solution we may commit your patch as-is.

Johannes



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