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    SubjectRe: apm emulation driver broken ?
    Rafael J. Wysocki wrote:
    > On Saturday, 17 of November 2007, Franck Bui-Huu wrote:
    >> Rafael J. Wysocki wrote:
    >>> However, using PF_NOFREEZE to prevent this from happening doesn't seem to be
    >>> a good idea.
    >> Indeed but...
    >>> I'd probably use wait_event_freezable() (defined in
    >>> include/linux/freezer.h) for that.
    >> ...I would just revert this bits from now to make sure this driver
    >> work again for v2.6.24.
    > I'd prefer not to.
    > The PF_NOFREEZE was not present in 2.6.23 already and I wouldn't like to
    > reintroduce it now.
    > Why do you think that using wait_event_freezable() would not work, BTW?

    I've never claimed this. I just said it may be safer to revert the
    changes for v2.6.24 and improve the current code for next releases.

    >>> It tries to send them fake signals and waits for them to freeze. If
    >>> they don't freeze within the timeout, it fails and clears their
    >>> TIF_FREEZE bits.
    >> But send_fake_signal() seems to wake up task in INTERRUPTIBLE state
    >> only. Looking at signal_wake_up(), it basically do:
    >> wake_up_state(t, TASK_INTERRUPTIBLE);
    >> What am I missing ?
    > Nothing. :-)
    > I didn't remember the change that made the freezer use TASK_INTERRUPTIBLE
    > explicitly in there (should have looked at the current code before replying).

    ok so now we agreed on this point, can we assert that a user
    land thread waiting for an event in an UNINTERRUPTIBLE state
    will prevent a suspend to happen ?

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      Last update: 2007-11-17 13:01    [W:0.022 / U:6.676 seconds]
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