Reattach/redetect allways connected umass device - is it possible ?

[M. Warner Losh]

In message: <39953.1112084492 at critter.freebsd.dk>
            "Poul-Henning Kamp" <phk at phk.freebsd.dk> writes:
: I will maintain, based on what little that I have read about user
: interfaces, that the logical and intuitive behaviour for a computing
: system is to notice immediately (< 2s) that a storage media has
: been removed.  I'm willing to be a tad more tolerant about inserts,
: but not much more than 5 seconds.

Then we'd have to poll every second in a sane way to accomplish that.
And finding the sane way that doesn't interfere with other bus usage
may be tricky.

Unless we're going to give events to the actual user (meaning userland
entities that inform the user in a friendly way), I'd maintain that
there's no difference between knowing that the media is ejected
immediately, and the time of next use.  The user experience will be
the same either way.

: I don't really care if our hardware is lame and brain-dead and needs
: to be polled in Shakespearan english by actors in victorian custumes,
: our job is to hide all that crap and give the system what to the
: users look like a consistent and predictable behaviour.

Assuming, of course, that it can be done with a reasonable level of
performance for the rest of the system, and that unintended
consequences of the polling don't happen (like keeping a disk
spinning all the time, when it would have spun down).  However, other
systems do effect polling in some fashion without spinning things up,
so it would be just a matter of finding these things.

In the short run, however, adding a few checks to critical parts of
the path, like daopen, would make the user experience much better.

Warner