Re: PROBLEM: MacBook makes whining noise when usb-uhci active

[Alan Stern <stern@rowland.harvard.edu>]

On Sat, 7 Jul 2007, Tim Hull wrote:

> [1.] One line summary of the problem: MacBook makes whining noise when
> usb-uhci loaded.

I assume you mean uhci-hcd.  usb-uhci is part of Linux 2.4, not 2.6.

> [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).

You have a USB keyboard, right?  So the ports are always in use -- 
unless you unplug the keyboard.

> 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.
> The same whine does occur in OS X that occurs in 2.6.22-rc7 (though it does
> NOT occur in 2.6.18)

I don't know what's causing the noise.  Maybe something operating at 
the UHCI controller's 1000-Hz frame rate is coupling to a speaker 
connection.

Anyway it's clearly a hardware problem, even if it is triggered by 
something in software.  About all I can suggest is to surround the 
MacBook with something sound-absorbent.  (Not very helpful, I agree.)

Alan Stern

-
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/