Messages in this thread | | | Date | Sun, 8 Jul 2007 02:24:12 +0200 | From | Richard Mittendorfer <> | Subject | Re: PROBLEM: MacBook makes whining noise when usb-uhci active |
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Also sprach "Tim Hull" <thully@umich.edu> (Sat, 7 Jul 2007 19:45:48 -0400): > [1.] One line summary of the problem: MacBook makes whining noise when > usb-uhci loaded. > [2.] Full description of the problem/report: On my MacBook (first > generation Core Duo 1.83GHz), I can hear a faint whining noise that > becomes audible when usb-uhci is loaded and remains audible except > when the USB ports are in use ( i.e. the noise temporarily stops when > I'm copying music to my iPod). This problem occurs on both 2.6.21 > and 2.6.22-rc7, but does not occur on 2.6.18. Unloading usb-uhci when > booted in 2.6.22-rc7 makes the whining noise stop, but the system is > useless in this state for obvious reasons. > [...] > [4.2.] Kernel .config file: > [...] > CONFIG_NO_HZ=y > [...] > # CONFIG_HZ_100 is not set > # CONFIG_HZ_250 is not set > # CONFIG_HZ_300 is not set > CONFIG_HZ_1000=y > CONFIG_HZ=1000 > [...] > CONFIG_X86_ACPI_CPUFREQ=y > [...]
This sounds like a known problem w/ some laptops. Maybe powersupply, noisy onboard conductors at 1000Hz, entering processor P-states and I've heard about it in context with USB too, IIRC....
As you have tickless timer enabled, CONFIG_HZ shouldn't trigger it, but you can check this with '$ vmstat 1' and watch the in(terrupts) field. They should be quite low.
To disable P-states follow the instructions on the link below.
As you have set CONFIG_USB_SUSPEND and it's noisy only when nothing is connected, unsetting it might be worth a try. But, AFAIK, 2.6.18 already had this feature?
Here's a link to a thinkpad related site talking about it: http://www.thinkwiki.org/wiki/Problem_with_high_pitch_noises
Looks like there are quite some different reasons causing it.
HTH & good luck, ritch - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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