On Tuesday 17 July 2007, Guillaume Pujol wrote: > Sorry for the double mail Andrea, this was supposed to be on list > (this is early in the morning here :/) ... > > ---------- Forwarded message ---------- > From: Guillaume Pujol <[EMAIL PROTECTED]> > Date: 17 juil. 2007 07:28 > Subject: Re: macbook pro & powertop > To: "[EMAIL PROTECTED]" <[EMAIL PROTECTED]> > > 2007/7/17, [EMAIL PROTECTED] <[EMAIL PROTECTED]>: > > well, yes, it's good, but not enough: my system still draws about > > 17-18 watt on idle (a mostly black tty in runlevel 1, only > > necessary kernel modules, filesystem mounted readonly, no audio, > > etc.), whereas mac os x gets away with as little as 11 (full > > functionality, all drivers, and graphic environment). so I'm > > wondering what causes such a big difference... > > The difference may come from the GPU (Radeon X1600 Mobility), which > oddly doesn't support powersaving under Linux (to be more specific, > the binary blob from ATI doesn't support that feature). This > results in the GPU always being at its full power, about 8 to 10W. > This behaviour only happens on the MacBook Pro Core2Duo from > november 2006 (maybe other laptops as well). > See http://www.phoronix.com/forums/showthread.php?t=3130
yes, that's exactly the model I have; I'm aware of that, and have stopped using the crappy fglrx long ago (and you can bet I will never buy a laptop with an ati card anymore). I used vesafb for a while (I don't need any fancy 3D stuff), then I'm currently using the development version of xf86-video-avivo (http://gitweb.freedesktop.org/?p=avivo/xf86-video-avivo.git), which does the job, but being based on reverse engineering of the binary stuff from amd, it will still take a long while to have powersaving features built in (but at least there's some source code, I could probably look into that and play with some registries). that said, do you think that a GPU can account for as much as 8 to 10W? isn't that too much? I'm happy about the number of wakeups per second, can keep them at a very low rate, even under X; I'll get myself to work on some kernel timers and some GUI applications that seem to abuse gtk timers, because I believe I can save a few tenths of watts and reduce heat as well. I also downloaded datasheets from intel for my chipset, to confirm whether the current kernel implements all available powersaving techniques, as time permits. but, still talking about cpufreq, does your own system show a big difference in power consumption when it runs at a lower clock/voltage? according to intel's specs, my cpu (T7400) works with the following voltage ranges: highest frequency: 1.0375-1.3000V lowest frequency: 0.7500-0.9500V that alone, to me, says that there may be quite a lot less heat and power consumption at lower frequencies/voltages. also, still according to the cpu datasheet, DC amps range all the way from 26.7A (both cores in C1) down to 9.9 (both cores in C4 enhanced deeper sleep), so that also should make a huge difference, or not? where am I wrong? andrea. _______________________________________________ Power mailing list [email protected] http://www.bughost.org/mailman/listinfo/power
