From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: Franck Bui-Huu <vagabon.xyz@gmail.com>
Subject: Re: apm emulation driver broken ?
Date: Sat, 17 Nov 2007 10:59:56 +0100
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References: <cda58cb80711160706l2cfac2b1p81c7a1090f228f2e@mail.gmail.com> <200711162220.56494.rjw@sisk.pl> <473EAC1A.1000205@gmail.com>
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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?

> > 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).

Greetings,
Rafael
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