Subject: Re: MobilePro 780 power management, ROM replacement
To: None <>
From: M. Warner Losh <>
List: port-hpcmips
Date: 03/06/2006 11:50:48
In message: <>
            Forest Bond <> writes:
: 2. I'm assuming that more tailored power management is what permits 
: Windows CE to retain its state information for such a dramatically 
: extended period of time.  As far as anyone is aware, is there any way to 
: improve NetBSD's power management?  I should think state would be 
: persistent for at least 6-10 hours with the unit in standby mode...

Windoes CE gets better power management during suspend by using a
deeper sleep mode than is available to NetBSD.  The reason for this is
that NetBSD lives in RAM, not ROM and on resume from hibernation, a
vector in the ROM is used.

During normal operations, much can be done to power down devices.
However, doing so is very platform specific and requires alot of
tweaking and trial and error to get right.

: 3. Has anyone had any luck replaceing the built in boot ROM's on their 
: handhelds?  Without this, every time my battery does finally die, I will 
: have to go through the Windows CE setup dialogs (which takes a couple of 
: minutes, and gets old fast) and then boot NetBSD from Windows CE.  This 
: is no fun at all.

I investigated heavily the possibility of replacing the boot ROMs in
the MobilePro 400 years ago.  This was a duanting task because at the
time there were no FLASH parts available that could be dropped in as a
replacement for the mask ROMs that were shipped with the 400.  This
was made a little easier because they were on a carrier board, but I
never quite worked out the necessary details to make flash chips work

The Mobile Pro 790 has built in flash memory, but I don't know if it
is the boot proms or not.  I do know that a portion of Windows CE
lives on this flash drive, and it can be used to influence the startup
sequence of WinCE, which might be useful in automatically starting