Re: NAK new drivers without proper power management?

On Monday, 12 February 2007 17:52, Pavel Machek wrote:
Hi!

Neither am I. I'm just asking that new drivers have power management as
standard.

What if the hardware doesn't support power management ?

You would still want to do the cleanup and configuration that you'd do
for module load/unload.

By adding dummy functions, wouldn't that just look awkward ?

If all you need to do is say 'I don't need to do anything' and we have a
shared function that does that, all we're talking about doing is adding
to your struct pci_device (or whatever)

.resume = generic_empty_resume;

To me at least, that doesn't look awkward, and says cleanly and clearly
that you've checked things over and decided you know what's required.

Actually, I'd like it to be

.resume = generic_empty_resume; /* Explain, why your driver needs no
resume */

Okay, but we can't define an empty .resume(), because, for example, the PCI's
generic suspend/resume won't be called.

I think we can introduce a "pm_safe" flag that will indicate if the driver
handles suspend/resume correctly. If we do it, we can flag all of the drivers
currently in the tree as "pm_safe" unless we know that they aren't. Next,
we can convert the core to fail the suspend for any driver that is not flagged
as "pm_safe". But I think that will take time.

In the meantime, I'd like to ask the authors of new drivers to define
error-returning .suspend() if they don't intend to define "real" .suspend()
and .resume() for now. When we are ready with the conversion, we'll be able
to drop the error-returning .suspend()s and clear "pm_safe" for them.

Greetings,
Rafael
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