[coreboot] H8 EC question

Charles Devereaux coreboot at guylhem.net
Tue Mar 10 09:19:44 CET 2015


Is there documentation for the H8 EC somewhere? (not just some code - even
if ec/lenovo/h8/acpi/ec.asl is very interesting)

There seem to be a discrepancy on battery charge thesholds, with ACPI
events such as "charge complete" (battery PNP0C0A:00 00000080 00000001)
happening at 80%, while in /proc/acpi/battery/BAT0/ it keeps charging.

At the moment,it's not possible to use tp-smapi, but it might be possible
to manually correct the threshold by writing to the EC, cf
http://www.thinkwiki.org/wiki/Talk:Maintenance. However, I see nothing at
offset 0x24 with ec-access.

I have no documentation for the H8 EC, but in
src/ec/quanta/it8518/acpi/ec.asl I see values that seem familiar for
thinkpads (ex: at offset 0x3A, the rfkill wifi/bluetooth/wwan) and a very
interesting reference, which seems to match thinkwiki discussion:
    Offset(0x03), // [Configuration Space 3]
 CHGR, 1, // Charge/Stop Charge threshold selector
// 0: Battery Charge Threshold / 1: Stop Battery Charge Threshold

    Offset(0x24), // [Battery Charge / Stop Charge Threshold Setting for
Primary Battery] (Read/Write)

For the rfkill things, I see :
    Offset(0x01), // [Configuration Space 1]
    ENBT, 1, // Enable to toggle the BlueTooth and BDC power state every
when the button is pressed.

Maybe the following control the USB port, to have a proper rfkill for wwan
(on EHCI port 1)

   1. Offset(0x26), // [Reserved]
   2. USP0, 1, // bit 0 USB0
   3. USP3, 1, // bit 1 USB3
   4. USP4, 1, // bit 2 USB4
   5. EHP0, 1, // bit 3 EHCI0
   6. EHP1, 1, // bit 4 EHCI1

Or :
    Offset(0x3B), // [Peripheral control 1]
    USBN, 1, // USB On

Anyway, it might not be a reliable description of the H8 features, so I
though I should ask. I am also interested in the codes returned by the EC
for various events to complete the ACPI tables. Any EC information is

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