[coreboot] x60 : TPM (and LEDs) point to ACPI issues

Charles Devereaux coreboot at guylhem.net
Thu Jul 17 21:55:29 CEST 2014


I tried to investigate the status of TPM support on the X60. Unlike on the
Acer C270, it is not used by coreboot at all (CONFIG_TPM is not set) - the
problems seems to be that it is not initialized.

On a standard bios, I can see at boot :

Jul  17 09:47:45 lenovo kernel: [    0.118724] pnp 00:0d: Plug and Play
ACPI device, IDs ATM1200 PNP0c31 (active)

With coreboot, nothing like that.  Booting with tpm_tis.force=1 still fails
(because of a missing PNP0C31 in the DSDT I believe)

Probing further, I found the device initialization on acpi_3.rom (after
running bios-extract on the standard bios). Running that though iasl, the
code is quite complex -  it is attached below.

Based on my understanding, ACPI tables are created on coreboot from
devicetree.cb file, which is quite different and that I don't fully
At the moment, I'm trying to use http://www.coreboot.org/pipermail/coreboot
gerrit/2014-May/010810.html as a base for ATM1200 and PNP0C31 definitions
(with apparently the same parameters (mem, etc) as in acpi_3.dsl

BTW, here seem to be other ACPI issues. With thinkpad_acpi, leds can only
be turned off. Doing anything else, one only gets the following warning:

[ 1033.498022] ACPI Warning: For \_SB_.PCI0.LPCB.EC__.LED_: Excess
arguments - needs 1, found 2 (20130328/nspredef-272)

Likewise, the stylus insertion/removal, (detected by a small swtich)
triggers TP_HKEY_EV_PEN_INSERTED and REMOVED in thinkpad-acpi, ie
ibm/hotkey HKEY 00000080 0000500b and ibm/hotkey HKEY 00000080 0000500c

Nothing like that with coreboot and thinkpad_acpi.

I haven't looked much into that, but the problem seems the same : a missing
or incomplete definition.
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