Wait a minute. We have both semantics in kernel drivers.
Ted's random does it the way you suggest it, but it does
look from the code that it hasn't been that way all the time.
I did it that way for the random driver because (a) it's useful, and (b)
normally you never block on writes to the random driver, so having
select and poll signal that the file descriptor becoming writable when
it needs entropy was useful for user-space random daemons, and didn't
take anything away. It was definitely non-standard semantics for
poll/select, though, and I wouldn't use this as an argument that any
other device driver should necessarily do this. /dev/random is
definitely a special case.
- Ted
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