On Thu, 2010-09-30 at 21:17 +0100, Russell King - ARM Linux wrote: > On Thu, Sep 30, 2010 at 01:08:07PM -0700, Daniel Walker wrote: > > That's actually what I had original, Russell offered this as an > > alternative. Now that I think about the stubs tho, I'm not sure it's > > that bad an idea. All the stubs would do is not put the core into a > > lower powermode, but would allow suspend. It wouldn't be very > > efficient , but suspend would work. > > If you just provide empty stubs, esp. for platform_cpu_die(), then an > attempt to take a CPU offline will result in it immediately restarting > back into the kernel - which will probably result in an oops as the > kernel won't be expecting the CPU to come back. Ok .. > If you make them spin, you'll eat power until the system powers them off. > As things currently stand though, we don't have enough code out of the > init sections to allow a SMP restart from power-off. So, S2RAM isn't > going to work on secondary processors at the moment _anyway_. When you say "SMP restart" do you mean resume? If I did make them spin wouldn't suspend and resume work at that point? > Current CPU hotplug implementations are based around taking CPUs offline > without powering them off for run-time power saving only. What I was thinking with the stubs is to fake the offlining. So it's not power efficient , but suspend still works. Daniel -- Sent by a consultant of the Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum. -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
