Re: Writing to the EC

[Carlos Corbacho <carlos@strangeworlds.co.uk>]

On Sunday 04 November 2007 19:55:40 Erik Andrén wrote:
> To make a long story short, I've hacked up a kernel module that dumps
> the EC

For acer_acpi, we have a Perl script that can do this from userspace (but
it should run on any other machine, since there's nothing Acer specific
about dumping the EC registers).

http://aceracpi.googlecode.com/svn/trunk/acer_ec/acer_ec.pl

./acer_ec.pl regs

(ACPI throws a few warnings in dmesg, because we're stepping on it's turf
a bit here, but it's far simpler than having to write a kernel module
just to get a few registers).
 
> My questions to you ACPI and EC gurus are:
> 
> 1. Is it possible that the EC is read-only from the OS perspective?

From the acer_acpi perspective, we've found that some EC registers are
read-only (e.g. on some laptops, there is a register to read the status
of the touchpad, but writes to it are ignored).

I imagine this is defined at the hardware level though, not by the OS.

> 3. Does anyone have a recommendation of programs to use for snooping I/O
> accesses in windows?

I did try playing around with writing my own simple application to access
the I/O ports, and then dump the EC data - unfortunately, I/O port programming
in Windows is "painful", to say the least.

-Carlos
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E-Mail: carlos@strangeworlds.co.uk
Web: strangeworlds.co.uk
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