It's very difficult to find out what to do when do you dont have any
schematics on the board, and i supose Compaq will probably never leave
the schematics of any iPAQ H3xxxx in public.
And there is not any detailed specification of hw either left in public.
> All figures for these will be subject to a specific set of conditions.
> For example, it's well known that a floating IO pin causes a higher power
> drain than if it is permanently held high or low by some means. To get
> maximal lifetime out of the battery, you really have to be extremely
> careful about the setting of each and every single IO line.
Here are muy big issue and question to Compaq, wich are all those IO pins
that i need to take care of ? While I (or we) dont know that, the iPAQ
will probably never get a sufficient low power consumption on sleep on
Linux.
> I've come across very little evidence that the above has been really
> thought about - the sleep state of all IO pins should be setup at
> initialisation time, and not left floating. Currently, I'd bet that
> most IO lines are left floating, which isn't really that good, both
> from an ESD point of view as well as a power saving view.
In the case of the iPAQ in arch/arm/mach-sa1100/h3600.c:
/* Configure suspend conditions */
PGSR = 0;
PWER = 0x1 | (1 << 31);
PCFR = PCFR_OPDE | PCFR_FP | PCFR_FS;
So on Linux the PCMCIA control signals and static chip select are floating
during sleep, but dont know if this is good or bad, again, I supose that
Compaq have the right answer.
Actually testing on my GraphicsClient+ floating the PCMCIA control signals
during sleep, you save aprox. ~ 5mA, getting a total power consumption on
sleep ~ 2mA on 5V.
/Benny
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