Re: [RFC] Disabling Devices

[David Brownell <david-b@pacbell.net>]

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On Monday 09 May 2005 11:06 am, Alan Stern wrote:
> There's an issue here that needs to be discussed explicitly.  How finely
> should the kernel allow userspace to control runtime power management?
> 
> ...
>     (B) Or should the kernel export a relatively small set of power 
> 	domains and a small set of primitives for each domain?  Like:
> 	suspend, turn off remote wakeup, go to full power, suspend
> 	after N seconds of inactivity?
> 
> ...
> 
> In general (A) most resembles what sysfs does right now.  I suspect that 
> (B) will be a better solution in the end.

Yes.


> Regarding Dave's comments about hdparm and xset dpms -- what matters most 
> about these interfaces is not that they are application-specific but that 
> they are ad-hoc. 

How does "application-specific" differ from "ad-hoc" though?
In practical terms; one is more pejorative than the other, but
how exactly does one measure a difference?

For example, the kernel doesn't know about X11 protocol at all,
or those particular IDE protocol requests.  And most folk would
probably say that it shouldn't need to ...


> I don't see why we can't strive to present a much more  
> uniform interface, even if it does describe widely varying subsystems.  I 
> also don't see anything wrong with implementing this interface by means of 
> sysfs instead of using driver-specific ioctls.

For new things, or things being generalized into kernel support,
I've no fundamental issue with using sysfs.  But for things that
are widely deployed today, I don't see much point in changing
interfaces.

- Dave

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