On Dec 12, 2006, at 12:00 PM, David Brownell wrote: > On Tuesday 19 September 2006 11:25 am, Pavel Machek wrote: >> >> Could you perhaps provide list of operating points for 770? It would >> help understanding a bit, I'd say. > > If there was a followup here, I missed it ... I think there was some sort of followup but I don't think it explictly listed the operating point values. > > ISTR that it doesn't use (formal) operating points, and that a lot > of the > basic SOC power savings (vs powering off the display or wifi) come > from a > different kind of mechanism entirely. Namely, a combination of > dynamic > tick with a modified system idle task, which enters one of the OMAP > low > power modes during those long periods between clock ticks or other > irqs. > > That's one of the standard power saving schemes used on OMAP1 > platforms > with Linux. Well sure but I think this discussion was about using the 770 as a specific example of operating point values. Here are the operating points used on omap1. The board specific part is just whether or not the board has a scalable voltage regulator. Omap1 has a fairly simple operating point definition and is, of course, not the latest h/w. This table comes from the DPM implementation on OMAP1 and is expressed as dividers. Name Voltage, DPLL multiplier, DPLL divider, cpu divider, tc divider (mem bus). 192 1300 16 1 1 2 168 1300 14 1 1 2 84 1300 14 1 2 2 84-1.1v 1050 14 1 2 2 60 1300 5 1 1 1 60-1.1v 1050 5 1 1 1 sleep-168 1300 14 1 0 -1 sleep-60 1300 1 2 0 2 Several other parameters could be added such as dsp and dsp mmu if one wanted to do more aggressive power management. btw, the parameter names I list above are from memory so I might have the order mixed up but you get the idea. The dpm utilities on sf.net also include 8 example operating points for pxa272. The operating point definition on pxa has ~5 parameters including voltage, cpu frequency and other clocks. > > - Dave > _______________________________________________ > linux-pm mailing list > linux-pm at lists.osdl.org > https://lists.osdl.org/mailman/listinfo/linux-pm
