[linux-dvb] Re: refactoring

[Andrew de Quincey <adq_dvb@lidskialf.net>]

On Monday 11 Oct 2004 13:14, Johannes Stezenbach wrote:
> On Mon, Oct 11, 2004 at 12:32:45PM +0100, Andrew de Quincey wrote:
> > On Monday 11 Oct 2004 12:29, Johannes Stezenbach wrote:
> > > Well, if the i2c bus and the devices on the bus aren't exposed
> > > at all in sysfs, then the DVB adapter driver could take care
> > > of it when called via PCI bus power management hooks. I don't
> > > think this is a good design, but it would work for PCI cards.
> >
> > I'm only talking about not exposing the bits of the frontend - exposing
> > the i2c bus is fine - you might have self-contained devices on it that it
> > makes sense for userspace to see (e.g. EEPROMs, analogue tv tuners).
>
> Then I suspect we might run into problems when the power management
> core decides to power down busses in the wrong order. Well, on PCI
> cards one could make the i2c adapter shutdown a noop, and do the i2c
> shutdown when the PCI adapter is shutdown. On embedded you have
> no such luck. You must power down the demod/PLL before the
> i2c bus goes to sleep. (There'll be probable ways to kludge
> around this, but it will never be clean&simple.)

Urgh, there is no nice solution to this. What is the least nasty?