[MinnowBoard] Problem with i2c on windows 8.1

Krau, Michael P michael.p.krau at intel.com
Fri Jul 10 16:57:49 UTC 2015


Other considerations regarding I2C on the MinnowBoard.  The system firmware only configures a few of theI2C buses on the MinnowBoard MAX because only a few buses are actually propagated on the Board to connectors.

On the Schematic (page 8) the one can see only three of the seven I2C buses actually have traces coming off of them.   In zero relative (one relative) numbering:
Bus 1(2) connects to test points 5 and 6 (this may not be enabled by default in the firmware, as access to the TP is not a common product platform feature).
Bus 5(6) connects to the low speed expansion port
Bus 6(7) connects to the high speed expansion port

The other buses have no physical connections, so the firmware  does not enable them.

Further enabling is not just turning the ports on, but providing data to the OS of their existence and configuration.  IF the ACPI tables do not reflect their presence in the systemthen there would be no indication to the OS of their existence.  Windows draws its cues from the ACPI tables for hardware capabilities of the platform.

But even then, if there is no physical connection available to use these buses then enabling (and publishing) them is not very beneficial.

In the comparison case of an Intel CRB, one would expect all of the I2C buses are propagated onto the board to some interface point or connector, therefore enabling them would be expected (and the ACPI tables for all would be present).  The purpose of a CRB is to ‘wring out’ the hardware and provide a complete set of hardware features to the user for test, development, experimentation and evaluation, making everything available and enabled for those purposes.  This is not the case on the MinnowBoard MAX, as only a few buses are physically available to the user, so only those few are enabled and published as well.

Thank you,


Michael Krau

While I am an Intel employee, I do not represent Intel and am not authorized to speak for Intel.

From: elinux-MinnowBoard [mailto:elinux-minnowboard-bounces at lists.elinux.org] On Behalf Of Berth-Olof Bergman
Sent: Friday, July 10, 2015 6:39 AM
To: MinnowBoard Development and Community Discussion
Subject: Re: [MinnowBoard] Problem with i2c on windows 8.1

Hi,

The missing SIO functions has to be enabled. The I/O pads for the missing functions has to be reconfigured if they are used by other signals. You need access to BWG (Bios Writers Guide) and the EDS documents. You need NDA with Intel to be able to download these documents.

BR,

B-O

10 jul 2015 kl. 15:08 skrev Tomislav Varga <tomislav.varga at dolotron.com<mailto:tomislav.varga at dolotron.com>>:

Hi,
Can you please tell us how to do it?

--
Tomislav Varga
Software Engineer


On Fri, Jul 10, 2015 at 11:38 AM, Berth-Olof Bergman <bo.bergman at winzenttech.com<mailto:bo.bergman at winzenttech.com>> wrote:
Yes, it’s possible.

B-O

> 10 jul 2015 kl. 10:44 skrev Tomislav Varga <tomislav.varga at dolotron.com<mailto:tomislav.varga at dolotron.com>>:
>
> Hi,
> We are trying to work with i2c on windows 8.1. Windows 7 IO drivers work on windows 8 when is in BIOS settings selected PCI instead APCI, problem is that only controllers #7 and #6 are visible. It seems that problem is somewhere in firmware since firmware for Intel CRB boards on same settings doesn't have problem, all seven controllers are visible.
>
> Is it posible to make all seven i2c controllers visible?
>
> --
> Tomislav Varga
> Software Engineer
>
>
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--

Tomislav Varga
Software Engineer

Dolotron d.o.o.
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