Subject: events (was Re: New IDE control program & changed to apmd )
To: None <>
From: Perry E. Metzger <>
List: tech-kern
Date: 11/20/1998 17:12:42
Jason and I have talked about putting in a generic "events" interface
for some time.

Basically, such an interface would allow kernel code or processes
running in userland to get "generic" events of various kinds,
indicating everything from power transitions to device
addition/removals to networking events of various sorts (like IP
addresses changing on various interfaces or interfaces going up/down), 
etc. Anything could be put into the events system.

To userland, the events interface would be via read/write to a file
descriptor that would be acquired either via a pseudodevice or a
special socket like the routing sockets we have now. (Jason is adamant
that he wants to use a socket -- I'm far from convinced, if only
because I prefer using file system name spaces, but he's much better
at this stuff than me.)

To the kernel, the interface would probably be via registration of

Via the interface, one could register for interest in certain kinds of 
events, and then get notification (via messages arriving on the file
descriptor or via the callbacks) of all the sorts of events we're
worrying about.


John Kohl writes:
> >>>>> "JS" == Jonathan Stone <jonathan@DSG.Stanford.EDU> writes:
> JS> For instance, i'd really like to see APM integrated with PCMCIA so
> JS> that one can, for instance, configure PCMCIA NICs to go into ``sleep
> JS> mode'' (or poweroff) if you go onto battery power, and powering them
> JS> up if you go onto mains power.  And  similar tricks if you have a
> JS> multi-homed laptop.
> Even more than that, we *have* to integrate pcmcia socket control with
> APM.  Some laptops drop power to PCMCIA sockets at suspend time, meaning
> you lose when you resume from sleep unless you've turned all the cards
> off by hand (just now possible with Jason's tweaks in -current).
> It's been on my list for a long time to sit down ad figure out a
> proposal for better cooperation between pcmcia and apm.  Real Life(tm)
> has intruded (e.g. I'm engaged and planning a wedding for next fall),
> and I'm not likely to get around to this anytime soon.
> If anybody out there wants to step up and propose a design, take
> comments, and implement it, I won't feel slighted about not getting to
> do it myself!
> -- 
> ==John Kohl <>, <>
> Write a poem, share your heart!
> Home page: <URL:>
> Note new home zip code as of July 1, 1998: 02476