[RFC PATCH 05/17] ARM: kernel: save/restore kernel IF
Russell King - ARM Linux
linux at arm.linux.org.uk
Tue Jul 12 06:19:48 EDT 2011
On Tue, Jul 12, 2011 at 11:12:57AM +0100, Lorenzo Pieralisi wrote:
> Thank you very much Russell for this recap.
> On Mon, Jul 11, 2011 at 07:40:10PM +0100, Russell King - ARM Linux wrote:
> > On Mon, Jul 11, 2011 at 03:00:47PM +0100, Lorenzo Pieralisi wrote:
> > > Well, short answer is no. On SMP we do need to save CPU registers
> > > but if just one single cpu is shutdown L2 is still on.
> > > cpu_suspend saves regs on the stack that has to be cleaned from
> > > L2 before shutting a CPU down which make things more complicated than
> > > they should.
> > Hang on. Please explain something to me here. You've mentioned a few
> > times that cpu_suspend() can't be used because of the L2 cache. Why
> > is this the case?
> > OMAP appears to have code in its sleep path - which has been converted
> > to cpu_suspend() support - to deal with the L2 issues.
> OMAP4, it is SMP configs I am talking about.
Seriously, that's not something which really concerns me at present
because suspend/resume in any form is not supported there in any form
All my comments are based on the mainline kernel. That's what I work
with. Everything elsewhere is not my concern.
So, let me say again. OMAP suspend/resume support _in_ _mainline_ will
be converted at the next merge window. As that's only OMAP3 _in_
_mainline_ which has the need for saving state etc, that's the only
OMAP code I have access to, and therefore that's the only thing which
I've been able to fix.
OMAP4 suspend/resume support doesn't exist in mainline and therefore
doesn't exist for me.
More information about the linux-arm-kernel