From mboxrd@z Thu Jan 1 00:00:00 1970 From: ezequiel.garcia@free-electrons.com (Ezequiel Garcia) Date: Mon, 17 Mar 2014 17:44:10 -0300 Subject: [PATCH v7 2/2] ARM hibernation / suspend-to-disk In-Reply-To: References: <1394016605-24120-1-git-send-email-sebastian.capella@linaro.org> <1394016605-24120-3-git-send-email-sebastian.capella@linaro.org> <20140316070917.GA3094@arch.cereza> Message-ID: <20140317204410.GA1118@arch.cereza> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mar 17, Sebastian Capella wrote: > On 16 March 2014 00:09, Ezequiel Garcia > wrote: > > On Mar 05, Sebastian Capella wrote: > > [..] > >> diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig > >> index 1f8fed9..83707702 100644 > >> --- a/arch/arm/mm/Kconfig > >> +++ b/arch/arm/mm/Kconfig > >> @@ -611,6 +611,11 @@ config CPU_USE_DOMAINS > >> config IO_36 > >> bool > >> > >> +config ARCH_HIBERNATION_POSSIBLE > ... > >> + default y if CPU_ARM920T || CPU_ARM926T || CPU_SA1100 || CPU_XSCALE || CPU_XSC3 || CPU_V6 || CPU_V6K || CPU_V7 > ... > > Is there any reason why CPU_FEROCEON is not listed here? FWIW, I've just built > > (but not really tested) a Kirkwood kernel with CONFIG_HIBERNATION=y. > No reason; I did not change this from the original patch I'd received. > I didn't try to get a comprehensive list of supported hardware. To > my understanding, the goal is to get the infrastructure in so that > people can start working on their platforms and add support for them. > Sure, no problem. If you consider that build-test is enough, feel free to put CPU_FEROCEON on that list. We added suspend/resume to feroceon not long ago. > > And is there any reason to put this config in arch/arm/mm/Kconfig, instead of > > in arch/arm/Kconfig, below ARCH_SUSPEND_POSSIBLE? > I don't have a reason. Anyone else have a comment on this? > Otherwise, I'll move it.. thanks! > It looked reasonable to me. > > I'm also puzzled about having two separate options for suspend and hibernate, > > maybe someone can explain me why a given CPU would support the former but not > > the latter? > It's part of having the generic hibernation implemented and available > but with architecture specific dependencies. Where an architecture > may not have support for hibernation, it will prevent compilation of > the generic hibernation support. For example, at the moment, ARM does > not support hibernation. [..] I guess my question wasn't clear. I mean to ask: Are there any other requirements on an ARM platform to support hibernation, other than suspend/resume support? If this is the *only* requirement, it seems to me we could make our ARCH_SUSPEND_POSSIBLE also select ARCH_HIBERNATION_POSSIBLE. Does this make sense? -- Ezequiel Garc?a, Free Electrons Embedded Linux, Kernel and Android Engineering http://free-electrons.com