Subject: RE: That darned TURBO switch
To: John F. Woods <jfw@jfwhome.funhouse.com>
From: Ernst du Toit <et@maxwell.ctech.ac.za>
List: port-i386
Date: 10/12/1997 21:45:24
>From my experience in my young, eh foolish days of PeeCee - the turdo switch 
function was different for each kind of 'board around, but then those were the 
days when boards were still designed. 

Some of the boards I installed did have a little program to toggle a flipflop 
for speed setting - can you do the CTRL-ALT-+ and - thing to toggle the speed 
under BIOS? IF you can then I guess its possible to rip the BIOS apart to try 
and figure out which address to tickle...

Sidenote, the ONLY mention I ever got for the splendid NON-Turdo mode was in a 
motherboard manual - So that the Lotus123 software protection on the install 
disk would not fall over itself I guess someone out there still needs this 
function to get that version of Lotus to install on their 400Mhz/MMZ Overzipped 
Plentium. Its a funny world.

On 12-Oct-97 John F. Woods wrote:
>I had to do an "emergency" reboot last night when I discovered that the reason
>for the constant stream of silo overflow messages was that my motherboard had
>gone out of "turbo" mode (i.e. had dropped to an 8MHz clock.  Ow.).  I have the
>switch disabled (it's not plugged in at all; my motherboard has three pins for
>the turbo switch, my chassis supplies a two-pin header, and I didn't know which
>pair of pins to try to connect...), but I suspect that this MB doesn't really
>appreciate letting that gate input float (is a berg pin really cheaper than a
>pull-up resistor???), and that a stray noise pulse toggled the state.
>
>Why am I pestering the NetBSD list?  I am curious if there is any way for an
>OS (in particular NetBSD) to sense the current setting of the CPU clock speed
>(or whatever it is that the TURBO switch affects) and to override it if it
>should get into the wrong state (or, perhaps, to just disable this misfeature
>entirely!).  I'd suspect there probably isn't a programmatic way to alter it
>(since MB manufacturers would have supplied a cheap program instead of an
>expensive switch), but hope springs eternal...

To disable, try what I did here - take an unused option jumper of one of the 
cards and just 'hardware' the turdo switch into 'on' mode forever. The center of
the three pins is usually the input to the gate and one other is GND the other 
might be HIGH - some boards do float the pin ( yeah I know...).   

Happy hacking
et