On Sunday, 27 May 2007 22:49, Matthew Garrett wrote:
Well, this was acutally invented before you've decided to remove the freezing
of tasks from the suspend code path (which I think is a mistake, but that's
only my personal opinion, so it doesn't matter very much ;-)) and I regard it
as a workaround.
Under the (optimistic, IMO) assumption that the relevant user space task won't
block on I/O with a suspended device involved or something like this.
BTW, I know of two subsystems that want their kernel threads to be frozen for
synchronization purposes. Please see these messages:
1) https://lists.linux-foundation.org/pipermail/linux-pm/2007-May/012592.html
(plus follow up)
2) http://marc.info/?l=linux-kernel&m=117919066830575&w=2
Your patch breaks them and I suspect there are more cases like these.
Besides, there's the hibernation that needs to freeze tasks for another reason,
so it needs some way to ensure that drivers won't request firmware while
the user land is frozen.
Yes, I think we should do this.
Greetings,
Rafael
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