Intel Clarifies HECI Usage For Arc Graphics' GSC

Stemming from the recent discussion of Intel's open-source Linux driver for Arc Graphics not yet running on POWER, another rather interesting support caveat was also raised. It turns out updating the GSC firmware for Arc Graphics hardware currently requires the Intel Management Engine (ME) functionality, which basically limits the graphics card firmware updating in turn to systems with Intel CPUs. (Update: See end of article.)

For now at least, Intel is only supporting the updating of their Graphics System Controller (GSC) firmware by way of the Intel Management Engine. Thus older Intel systems without HECI-over-MEI or non-Intel systems like AMD CPUs or AArch64 / POWER / RISC-V systems are not able to apply the GSC firmware updates to Arc Graphics cards.

Lead LVFS/Fwupd developer Richard Hughes pointed out this support caveat following the recent Arc Graphics + POWER article.

And it's not going to be updatable without the CSME functionality. The Arc card firmware is updated using HECI-over-MEI which means it's only available on Intel machines only. See https://t.co/QbGB8mc3l0

— Richard Hughes (@hughsient) November 4, 2022

It's nice that the Intel Graphics System Controller will be updatable under Linux by way of an Fwupd plugin, but unfortunate that it relies upon Intel Management Engine functionality for facilitating the update. Handling the GSC firmware updates via the Intel Management Engine interface is done in the name of security.

Details on the Fwupd intel-gsc firmware updating with Fwupd can be found via Fwupd on GitHub. We'll see if Intel ends up changing how the GSC firmware can be updated in the future or will remain tied to the Intel ME in what is then effectively an Intel CPU mandate for Arc Graphics GSC firmware updating.

Update: Intel reached out to say firmware updating will work on AMD platforms, but awaiting to hear futher details / answers to questions given the statements on Fwupd with the Intel-authored firmware updating plugin, etc, to see if it's currently implemented or just planned for the future. Namely rather confusing as Intel's own GSC Fwupd plugin continues to carry the text that non-Intel machines are not supported.

Intel Arc doesn't require the host CSME to update firmware. Firmware updates will work on both AMD or Intel platforms. Arc has its own Graphics Security Control for firmware updates leveraging existing technology like HECI interface protocol to implement the firmware update flow.

— Intel Graphics (@IntelGraphics) November 5, 2022

Update (8 Nov): I've heard back now from Intel with more information on their HECI usage by the Graphics System Controller. The GSC exposes an HECI interface but it turns out to not depend upon the motherboard chipset's HECI / CSME. Their explanation is:

Our discrete GPUs include a security controller that happens to also implement a HECI interface in a similar manner to the HECI interface that exists in the CSME on the PCH. That is, the HECI interface that we are referring to when we state that our discrete GPU uses HECI to perform a firmware update. We do not have a dependency on PCH functionality for our firmware update flow. A separate MEI driver is loaded for the Arc HECI interface.

This morning they have now also corrected the README for the intel-gsc firmware updating plugin to remove their prior comment saying lack of support for non-Intel systems. Thus it turns out the earlier information was incorrect and GSC firmware updating should work out fine on Arc Graphics for both Intel and AMD CPU systems.