Re: Looking for some pointers on WMI/EC access

[Corentin Chary <corentin.chary@gmail.com>]

On Tue, Apr 20, 2010 at 9:21 AM, Corentin Chary
<corentin.chary@gmail.com> wrote:
> On Tue, Apr 20, 2010 at 8:52 AM, Florian Echtler <floe@butterbrot.org> wrote:
>> Hello Corentin,
>>
>>> >> > First, I've dumped the DSDT and browsed through it. I've found a _WDT
>>> >> > section, and wmidump shows:
>>> >> Wow, someone actually used that tool ^^
>>> >> A Quick hint would be to look at
>>> >> https://patchwork.kernel.org/patch/87210/ which is basically a really
>>> >> short example of what a wmi-driver is.
>>> >> Just change the guid, buid/load, push some hotkeys, see dmesg, edit
>>> >> the keymap, build, load, test ..
>>> > Thanks for the pointer - I've given it a quick try and the driver loads
>>> > successfully, however, the event doesn't seem to be triggered. I've put
>>> > a printk into the eeepc_wmi_notify function, and this is seemingly never
>>> > called.. although I believe this may be the right direction, as the GUID
>>> > from the eeepc driver (ABBC0F72-8EA1-11D1-00A0-C90629100000) and the one
>>> > from my Lenovo (ABBC0F20-8EA1-11D1-00A0-C90629100000) differ only by a
>>> > single byte.
>>> This is not the first laptop with an asus-like dsdt, some Lenovo are
>>> supported by asus-laptop.
>>> > Could this event be disabled somehow?
>>> Don't know, can you send the result of acpidump ?
>> I've attached the output of acpidump as well as the decompiled DSDT.
>
> Looking at your dsdt:
>
> BUF1 and BUF2 contains some easy to find data:
>
>                        CreateByteField (BUF1, 0x01, EID1)
>                        CreateByteField (BUF1, 0x02, ERQ0)
>                        CreateByteField (BUF1, 0x03, BRIL)
>                        CreateByteField (BUF1, 0x04, SKEY)
>                        CreateByteField (BUF1, 0x08, BLUE)  bluetooth
>                        CreateByteField (BUF1, 0x09, WLAN) wifi
>                        CreateByteField (BUF1, 0x0A, WL3G) 3g
>                        CreateByteField (BUF1, 0x0B, WMAX) wimax
>                        CreateByteField (BUF1, 0x0C, GLSW)
>                        CreateByteField (BUF1, 0x10, TPST) touchpad ?
>                        CreateByteField (BUF1, 0x11, SLMD)
>                        CreateByteField (BUF1, 0x12, SBR0) brightness ?
>                        CreateByteField (BUF1, 0x13, SBR1)
>                        CreateByteField (BUF1, 0x14, SBR2)
>                        CreateByteField (BUF1, 0x15, SBBR)
>                        CreateByteField (BUF1, 0x16, SBLI)
>                        CreateByteField (BUF1, 0x17, TBMD)
>                        CreateByteField (BUF1, 0x18, RTAG)
>
>                        CreateByteField (BUF2, 0x01, EID2)
>                        CreateByteField (BUF2, 0x08, BIV0)
>                        CreateByteField (BUF2, 0x09, BIV1)
>                        CreateByteField (BUF2, 0x0A, BIV2)
>                        CreateByteField (BUF2, 0x0B, BIV3)
>                        CreateByteField (BUF2, 0x0C, BIV4)
>                        CreateByteField (BUF2, 0x0D, BIV5)
>                        CreateByteField (BUF2, 0x0E, BIV6)
>                        CreateByteField (BUF2, 0x0F, BIV7)
>                        CreateByteField (BUF2, 0x10, WMIV)
>                        CreateByteField (BUF2, 0x18, BRMX) brightness max ?
>                        CreateByteField (BUF2, 0x20, BAT1) battery
>                        CreateByteField (BUF2, 0x21, BAT2) battery
>                        CreateByteField (BUF2, 0x22, ACDC) music ? :p
>                        CreateByteField (BUF2, 0x23, CPUT) cpu temp ?
>                        CreateByteField (BUF2, 0x24, VGAT)
>                        CreateByteField (BUF2, 0x25, CDT1)
>                        CreateByteField (BUF2, 0x26, CDT2)
>                        CreateByteField (BUF2, 0x27, FSP1)
>                        CreateByteField (BUF2, 0x28, FSP2)
>
>
> Looking at _INI :
>       Store (\_SB.BRNS, BRMX) probably means "set the brightness to
> the maximum brightness"
>
> WQIO returns both BUF1 and BUF2, you can get it with wmi_query_block()
>
> WSIO calls CPSR and CPSR store the argument in INBF.
> BY00, BY01, ... BY31, BGTX, BGTY, BGTZ etc ... are used to access
> specific bytes in INBF :
>                        CreateByteField (INBF, 0x00, BY00)
>                        CreateByteField (INBF, 0x01, BY01)
>                        CreateByteField (INBF, 0x02, BY02)
>                        CreateByteField (INBF, 0x03, BY03)
>                        CreateByteField (INBF, 0x04, BY04)
>                        CreateByteField (INBF, 0x05, BY05)
>
>
> CSPR wants BY00 to be 0x01 and BY01 to be 0x10 to do something.
> It calls CMD0 (BY08, BY09, BY10, BY11, BY16)
>
> ERQ0 (present in BUF1) is compared to Arg2 (BY09) == 0x1
> if true, it will store some values and call notify

//Ooops, message sent, but not finished ... Continuing here:

else it will call UWED with BY08, BY09, BY16.

Then, BY08 is stored in _T_0 which is used to find what code to execute.
Now, you need to look at what each value of _T_0 will do.


Looking at the rest of the dsdt:

Method (GECN, 1, NotSerialized)
Method (SECN, 2, Serialized)

are very interesting:

GECN is used to get status, and SECN to set status.

For example, use \_SB.GECN(0x03) to get bluetooth status
And \_SB.SECN(0x03, 0x01) to enable bluetooth.
I don't really understand what DECN is used for, maybe to know if a
device is present (or maybe just switch GECN and DECN).




-- 
Corentin Chary
http://xf.iksaif.net
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