In my view this question is not a duplicate of the indicated question. I specifically want to also know what is the reason EHCI Hand off setting exists on XHCI motherboard where all USB ports are essentially controlled by XHCI. Thanks.
This question is close to this one on SU. There OP wants to know what is the ideal setting for XHCI Handoff when running Windows 7. Should it be Enabled or Disabled. So while it partly addresses the issue I have two related questions independent of the OS installed.
- What is the actual meaning of Handoff?
- On modern boards where (as per my understanding, see the below post quote from the manual) even USB 2.0 is wired to XHCI controller, what purpose does EHCI Handoff setting do?
The link on B350-DASH below shall open the Motherboard Manual. The exact description is also pasted below as a Quote.
The Gigabyte motherboard B350M-DASH has following options in BIOS Settings
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)
Moreover it seems that it's the Chipset & CPU that handles the USB 3 ports on AM4 Platform.
So where does EHCI come in for EHCI Handoff?
Chipset: - 2 x USB 3.1 Gen 2 Type-A ports (red) on the back panel - 2 x USB 3.1 Gen 1 ports available through the internal USB header - 4 x USB 2.0/1.1 ports available through the internal USB headers
CPU: - 4 x USB 3.1 Gen 1 ports on the back panel