From mboxrd@z Thu Jan 1 00:00:00 1970 From: linux@arm.linux.org.uk (Russell King - ARM Linux) Date: Tue, 12 Jul 2011 11:19:48 +0100 Subject: [RFC PATCH 05/17] ARM: kernel: save/restore kernel IF In-Reply-To: <20110712101252.GA9604@e102568-lin.cambridge.arm.com> References: <1310053830-23779-1-git-send-email-lorenzo.pieralisi@arm.com> <1310053830-23779-6-git-send-email-lorenzo.pieralisi@arm.com> <20110711140047.GA346@e102568-lin.cambridge.arm.com> <20110711184010.GB8486@n2100.arm.linux.org.uk> <20110712101252.GA9604@e102568-lin.cambridge.arm.com> Message-ID: <20110712101948.GD23270@n2100.arm.linux.org.uk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 in mainline. 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.