[OLPC-devel] Why ACPI DSDT tables?

[Jim Gettys]

Dave,

A lot of the power management stuff (battery charging, on AC power,
wakeup of the Geode) is done in the embedded controller (EC).  We have
to have some sort of interface between it and the rest of the system.  

And yes, on the iPAQ (and maybe on the Nokia 770), we emulated APM, just
for simplicity's sake.

If you are seriously suggesting that we do something other than ACPI for
the internal interfaces from the EC and the Geode, (something that
Quanta is already familiar with), then you need to make the case now in
concert with Ray Tseng, while the code is still being written (by Ray
and his team).

I'm very reluctant to see is another, different set of user space
interfaces happen than those provided by the widely used ACPI and APM
interfaces: there lies madness for people like David, and others working
in user space.
                              Regards,
                                  - Jim


On Mon, 2006-07-10 at 20:16 +0100, David Woodhouse wrote:
> On Mon, 2006-07-10 at 12:19 -0400, David Zeuthen wrote:
> > How do you expect to export things like battery and "on ac power?"
> > information to userspace? Frankly, the interfaces the Linux kernel
> > exports for these all suck (/proc/acpi, apm, pmu, etc.) but we work
> > around that in HAL... and now you want to add *another* interface? 
> 
> The common approach seems to be to provide /proc/apm -- even on machines
> with a PMU we do that. Many ARM machines do likewise, etc. 
> 
> Yes, that kernel<->user interface isn't ideal, and if you start using
> ACPI the lack of consistency sucks because it doesn't follow that
> defacto standard -- but that's a separate issue, and is no excuse for
> actually using AML crap instead of proper drivers.
> 
-- 
Jim Gettys
One Laptop Per Child