eHCI Handoff setting on Gigabyte B350 AM4 boards

Sep 26, 2018
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Hi,
My earlier question on this site gives an idea that in fact on AM4 chipsets have even USB 2.0 controlled by xHCI controller.

Recently while reviewing Gigabyte B350 AM4 board manual, I came across ehci handoff setting in its BIOS.

Some boards have a toggle switch to switch between echi & xhci while Gigabyte seems to have implemented separate options configurable in BIOS. The options are

XHCI Hand-off
Determines whether to enable XHCI Hand-off feature for an operating system without XHCI Hand-off support. (Default: Enabled)

EHCI Hand-off
Determines whether to enable EHCI Hand-off feature for an operating system without EHCI Hand-off support. (Default: Disabled)
However when AM4 chipsets no longer have ehci controller, I wonder what purpose would ehci handoff fulfill on Gigabyte AM4 boards.

Can there be some technical explanation as to why this option exists when even USB 2 is controlled by xhci?

Thanks.
 

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