New port: pvrxxx for Hauppauge PVR150/500

[Rick C. Petty]

On Mon, Oct 16, 2006 at 08:40:04AM +0200, usleepless at gmail.com wrote:
> 
> correct. however, ivtv seems to be able to download it much faster. i
> have experimented with speeding up the i2c stuff, but failed ( ie gave
> up ).

Hmm, I could take a look at it.  In my infinite spare time...

> >Feel free (anyone) to look into the iic code and pull it out from under
> >GIANT.
> 
> will that help? reason i ask is because with the i2c, the cpu is
> responsible for every bit-switch/line-switch in the protocol. so
> through the pci-interface, it tells the card to pull the line up, you
> wait a very short time, and tell it to pull the i2c-line down. etc...

I'm assuming there is little (if any) delay between driving the data line
and then toggling the clock line.  I think as long as your timing loop
guarantees that at most you're transferring 400 kbit/s, you should be fine.
I think this can be done by using some type of timer in the kernel, so you
can go in & out of the kernel and allow other interrupts to process, etc.

> this weekend, i removed Giant from the pvrxxx-driver itself. i am on
> UP myself, so i don't know what it is good for.

Hrm, I thought GIANT was more useful than just for SMP.  I guess it depends
on whether the cxm driver sits in a timing loop, and whether other
interrupts can happen while you're programming the DSP chip.  My guess is
that you'll notice some improvement even in UP.

-- Rick C. Petty