Hotstart / quickstart buttons?

[Kyle Evans]

Hi,

I am hopping I can get some help with GRUB_DEFAULT_BUTTON. I have these 
hotkeys on my laptop that use the Windows hotstart interface (PNP0C32). 
They call this quickstart in linux.

The purpose behind these keys is so that someone can start a multimedia 
program or similar from a power off state. But I want to use them to 
select which version of GNU/Linux I want to boot. I know 
GRUB_DEFAULT_BUTTON is only designed for one button, but bear with me, 
I'm using it to test the functionality of such a system.

I spent a lot of time in the DSDT and the EC looking for a way to get 
these buttons working during runtime, so I am familiar with the DSDT and 
what offset the button codes are stored.

Now, when I try doing things by the book and look at the nvram, address 
0x5A is the sole variable, and things looked great. I had 0x7a, 0x7b, & 
7x7c for power button, QBTN, & DBTN. But it isn't consistent, i.e. 
related. It wasn't working right so I ran the if cmostest 104:0-7 and 
the numbers did not match my initial numbers. So, I dumped /dev/nvram 
again to verify and found the numbers are indeed not the same, I just 
got 0xa3 for DBTN != 0x7c.

I have found previously that the internal button codes for the two 
quickstart keys that turn on the device are QBTN=0x04 & DBTN=0x05. 
During runtime these buttons are placed in EC offset 0xA2 before being 
used to generate a real keycode. I am not sure if that offset contains 
the code at boot because the PNP0C32 device tests another register for 
these values. That register is offset 0xC2 from the top of the DSDT. My 
question is, how can I translate those offsets into something grub can 
read?

Here are some snips from the DSDT. IVIM is the register used by PNP0C32 
and QBBB is an SMBus buffer inside the EC. The keycode value is the same 
in both locations, but I was not able to find a direct link between the two.

DefinitionBlock ("dsdt.aml", "DSDT", 1, "HP    ", "30F1    ", 0xF0000000)
{
...
    IndexField (INDX, DATA, ByteAcc, NoLock, Preserve)
    {
...
                Offset (0xC2),
        IVIM,   8,
...
    }


                    OperationRegion (ERAM, EmbeddedControl, Zero, 0xFF)
                    Field (ERAM, ByteAcc, NoLock, Preserve)
                    {
                        ...
                                Offset (0xA2),
                        QBBB,   8,
                        ...
                    }

Thanks,
Kyle Evans