Messages in this thread | | | Date | Thu, 25 Dec 2008 10:16:48 -0600 | From | Robert Hancock <> | Subject | Re: Question about not saving power |
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Alexander E. Patrakov wrote: > On Wednesday 24 December 2008 12:02:53 Robert Hancock wrote: >> Alexander E. Patrakov wrote: >>> Hello. >>> >>> I tried playing with some audio apps like JACK and fluidsynth, and >>> noticed the following. If I set the parameters in JACK so that the >>> latency becomes less than ~10 milliseconds, a faint tone appears in the >>> headphones connected to the onboard sound card. >>> >>> I guess that its frequency is the tone is the same as that of the >>> interrupts generated by the sound card. The tone disappears if I run >>> something like "while : ; do : ; done" that consumes CPU time >>> continuously, so I guess this has something to do with the power-saving >>> features and less-than-perfect PSU. >>> >>> My question is: what are my options (like kernel parameters) to disable >>> power- saving features, other than running such CPU-eating process >>> continuously? >> You can try booting with idle=poll on kernel command line, so the CPU >> will not enter halt states.. > > This mostly helped. Now the tone disappeared, but there are noises (not > xruns!) caused by the onboard graphics card when KDE4 draws something. I > disabled the effects to reduce the noise, but it didn't fully help (there is > still some "zzzzz" when I move the mouse over the taskbar so that different > window buttons are highlighted). The noise exists both in the connector for > headphones on the front panel, and in the green connector at the back of the > computer, but in the second connector, it is much softer. > > The board is Intel DG965SS, and the graphics ship is: > > 00:02.0 0300: 8086:29a2 (rev 02) > 00:02.1 0380: 8086:29a3 (rev 02) > > or, with names instead of the numbers, > > 00:02.0 VGA compatible controller: Intel Corporation 82G965 Integrated > Graphics Controller (rev 02) > 00:02.1 Display controller: Intel Corporation 82G965 Integrated Graphics > Controller (rev 02) > > Intel developers: could you please add some workaround to the "intel" driver, > so that the GPU always stays busy (and thus draws the constant amount of > power)? And please tell the hardware designers so that for the future boards, > this interference between graphics and audio should not happen. Add separate > stabilizers and filters for the power supply of the audio chip, carefully > design the wiring so that the "noisy" lines don't get near anything related to > audio. >
I think you may be expecting too much from the analog output quality for onboard sound, this is a common problem on many boards. If you really want high quality analog output you usually have to go for a separate sound card which usually have much better filtering.
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