[ltp] T30 Serial Port

[wes schreiner]

Tino Keitel wrote:

>On Thu, Sep 29, 2005 at 23:17:13 -0500, wes schreiner wrote:
>  
>
>>Richard Mancusi wrote:
>>
>>    
>>
>>>Thanks for the reply.  So, I will assume that I have not
>>>done any harm.
>>>
>>>
>>>      
>>>
>>You haven't done any harm, but the reason that the serial port is 
>>disabled by default is that few people actually use it, yet when it is 
>>enabled it does draw power.  So it is disabled in order to reduce the 
>>drain on the battery by a small amount.  In general, if you want maximum 
>>run time on battery, you should disable everything you aren't going to use.
>>    
>>
>
>Is there a way to do this for serial, parallel and IrDA without the
>BIOS, e.g. at run time, especially on a T23?
>  
>

Maybe. tpctl might be able to do it. Looking at the tpctl home page 
<http://tpctl.sourceforge.net/> doesn't say one way or the other, you 
would have to try it. Another possibility is to use setpnp to change the 
resource settings. That would work with a 2.6 kernel, but you would need 
a patched 2.4 kernel to have pnp support. The changes made by tpctl only 
last until the next reboot. With setpnp you have the option of making a 
temporary change that reverts on reboot, or making a permanent change.

I don't know how much battery life one can gain by shutting off the 
ports. I think larger gains would come from spinning down the hard drive 
sooner and running noflushd to delay spinning up the hard drive. Also if 
one mounts the drive(s) with the noatime option then spin up will happen 
less often. I've done all the above on my lowly ThinkPad 600E but I 
don't run off the battery enough to really notice how much any of these 
tweaks help. You would have to try things out on your T23 and see what 
happens.

wes