Hello, On Tue, 4 May 2010, Alan Stern wrote: > Another thing that Kevin is missing: There is more to the system than > the devices and the CPU. For example: RAM, an embedded controller (on > modern desktop/laptop systems), a power supply, and so on. Dynamic PM > for the CPU and the devices won't power-down these things, but system > PM will. No. A dynamic PM-based kernel can, and in the case of the mainline Linux code running on OMAP, does, power down RAM[1] and the power supply[2]. Since the CPU is already powered off when it is time for this to happen, so this is done under autonomous hardware control. We currently use CPUIdle[3] to choose whether to program the SoC hardware to enable this autonomous power control before it goes off, depending on the required wakeup latency for timers and PM constraints. - Paul 1. (technically, put the RAM into self-refresh mode): http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=arch/arm/mach-omap2/sleep34xx.S/sleep34xx.S;h=d522cd70bf53485d0a3af2453845777e3a89edd7;hb=4fc4c3ce0dc1096cbd0daa3fe8f6905cbec2b87e#l204 2. http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=arch/arm/mach-omap2/sleep34xx.S/sleep34xx.S;h=d522cd70bf53485d0a3af2453845777e3a89edd7;hb=4fc4c3ce0dc1096cbd0daa3fe8f6905cbec2b87e#l204 3. http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=arch/arm/mach-omap2/cpuidle34xx.c;h=3d3d035db9aff62ce522e0080e570cfdbf8e70cc;hb=4462dc02842698f173f518c1f5ce79c0fb89395a#l292 _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
