Re: [Suspend-devel] [PATCH -mm 1/2]: PM: Fix handling of stopped tasks

["Rafael J. Wysocki" <rjw@sisk.pl>]

On Wednesday, 6 December 2006 00:45, Pavel Machek wrote:
> Hi!
> 
> > > > ...after resume.
> > > 
> > > This is because of how signal_wake_up() works, I think..
> > > 
> > > > But I think it is right approach.
> > 
> > Okay, with the appended patch applied everything seems to work and I don't
> > see any undesirable side-effects.
> 
> I promise to try it... tommorow. Looks very good to me.

Unfortunately there's one problem with it.

To reproduce it I run "gdb /bin/cat", execute "run" in gdb and press ^Z twice
to stop both processes.  Next I suspend and resume and run "fg" to get the gdb
back.and press "Enter" to get the prompt.  Then, it turns out that the
terminal echo doesn't work and "Enter" doesn't make it go to the next line.
I can recover from this state by typing "fg+Enter" (with no echo) so that
/bin/cat gets the continuation signal and it restores the terminal settings,
apparently.

This means, however, that with this patch the behavior of a process (gdb)
after the resume may be different to its normal behavior, which is wrong.

With my original [1/2] this problem doesn't appear (ie. after the resume gdb
behaves normally).  Thus I think that, although this patch is much more
elegant, my original [1/2] is a safer solution, because we can say exactly
what it does.

Greetings,
Rafael


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