Re: poll() in 2.6 and beyond

[Roland Dreier <roland@topspin.com>]

    Richard> Well the device's poll function isn't getting called the
    Richard> second time with 2.6.0. I never checked it in 2.4.x
    Richard> because it always worked.  This problem occurs in a
    Richard> driver that only returns the fact that one event
    Richard> occurred. When it failed to report the event when built
    Richard> with a newer kernel, I added diagnostics which showed
    Richard> that the poll in the driver was only called once --and
    Richard> that the return from poll_wait happened immediately.

Your driver is buggy.  It's not surprising since you fundamentally
don't understand the kernel interface you're trying to use.

    Richard> So, if the poll_wait isn't a wait-function, but just some
    Richard> add-wakeup to the queue function, then its name probably
    Richard> should have been changed when it changed. At one time it
    Richard> did, truly, wait until it was awakened with
    Richard> wake_up_interruptible.

When did it change?  Show me a kernel version where poll_wait() waited
until the driver woke it up.  (Kernel versions at least as far back as
1.0 are readily available from kernel.org, so it should be easy for
you)

 - Roland