Re: broken suspend [Was: 2.6.24-rc2-mm1]

Alan Stern
2007-11-19T03:05:01Z

On Sun, 18 Nov 2007, Jiri Slaby wrote:

> > gives coretemp_cpu_callback -> coretemp_device_remove ->
> > platform_device_unregister, so coretemp seems to be what I have and you don't.

Yes.

For the coretemp developers: coretemp_cpu_callback() needs to be more
careful about what it does. During a system sleep transition (suspend,
hibernate, resume) it isn't possible to register or unregister a
device. Attempts to register will fail and attempts to unregister will
block until the system sleep is over -- and for this callback that
means hanging.

It's not clear what the best way is to fix this. Perhaps the CPU
notification should be sent along with a special flag indicating that
the CPU transition is part of a system sleep (although this seems
racy). Perhaps the driver should notice when a system sleep begins,
and defer all CPU-change handling until after the sleep is over.

Alan Stern