Cloned devices

Both boxes got the same 57 emulated devices, one box at a time behind one hub. Medius had imperfect clones off, as it ships.

Native data reaching the PC

Device	Stock	Medius	Result
Three mice with a 1 ms interval8-bit and 16-bit axes, and a mouse and keyboard in one	All data arrives	All data arrives	Equal
Boot keyboard	All data arrives	All data arrives	Equal
Mouse with a second, streaming HID interface	All data arrives	All data arrives	Equal
Three unusual HID interfacesAlternate settings, a 64-byte endpoint, the HID descriptor after the endpoint	All data arrives	All data arrives	Equal
Two unusual interface layoutsA gap in the interface numbers, numbering from 1	All data arrives	All data arrives	Equal
Four devices slow to give their report descriptor450 or 700 ms late, or refused	All data arrives	All data arrives	Equal
Two mice, with and without a device qualifier	All data arrives	All data arrives	Equal
Five mice with an 8 or 10 ms intervalIncluding a two-mouse device and a mouse with two configurations	All data arrives	All data arrives	Equal
Mouse with a 1,500-byte report descriptor	An interface sends nothing	All data arrives	Medius
Wooting 60HE+	An interface sends nothing	Not cloned	Medius
Mouse with a vendor interface, six IN endpoints	An interface sends nothing	Not cloned	Medius
Mouse claiming a 3,000-byte report descriptorIt sends 50 bytes, which the PC pads to 3,000 with zeros	All data arrives	Not cloned	Stock
Mouse with an unused second configuration	All data arrives	Not cloned	Stock
Mouse with a vendor interface of nine settings	All data arrives	All data arrives	Equal
Mouse with an 8-byte endpoint 0	All data arrives	All data arrives	Equal
Mouse with a 16-byte endpoint 0	All data arrives	All data arrives	Equal
Mouse with a 32-byte endpoint 0	All data arrives	All data arrives	Equal
Mouse with name and serial strings	All data arrives	All data arrives	Equal
HID interface numbered 200 beside a vendor one numbered 60	All data arrives	All data arrives	Equal
Gaming mouse	All data arrives	All data arrives	Equal
Keyboard	All data arrives	All data arrives	Equal
High-speed mouse	All data arrives	All data arrives	Equal
Mouse that stalls its endpoint after 200 reports	All data arrives	All data arrives	Equal

Clone faithfulness

Device	Stock	Medius	Result
Three mice with a 1 ms interval8-bit and 16-bit axes, and a mouse and keyboard in one	Faithful	Faithful	Equal
Boot keyboard	Faithful	Faithful	Equal
Mouse with a second, streaming HID interface	Faithful	Faithful	Equal
Five mice with a streaming vendor interface	Faithful	Faithful	Equal
Six unusual HID interfacesAlternate settings, a 64-byte endpoint, two IN endpoints, OUT only, the HID descriptor after the endpoint, a physical descriptor first	Faithful	Faithful	Equal
Four unusual interface layoutsAn alternate setting, a gap in the interface numbers, numbering from 1, ten interfaces	Faithful	Faithful	Equal
Four devices slow to give their report descriptor450 or 700 ms late, or refused	Faithful	Faithful	Equal
XInput pad and a USB serial device	Faithful	Faithful	Equal
Two mice, with and without a device qualifier	Faithful	Faithful	Equal
Five mice with an 8 or 10 ms intervalIncluding a two-mouse device and a mouse with two configurations	Imperfect	Faithful	MediusStock defect
Device with a second control endpoint	Imperfect	Faithful	Medius
Mouse with a 1,500-byte report descriptor	Imperfect	Faithful	Medius
Mouse with an 8-byte endpoint 0	Faithful	Faithful	Equal
Mouse with a 16-byte endpoint 0	Faithful	Faithful	Equal
Mouse with a 32-byte endpoint 0	Faithful	Faithful	Equal
Mouse with name and serial strings	Faithful	Faithful	Equal
Mouse with a vendor interface of nine settings	Faithful	Faithful	Equal
Vendor interface numbered 12	Faithful	Faithful	Equal
HID interface numbered 200 beside a vendor one numbered 60	Faithful	Faithful	Equal

Time from device appearing to clone configured, min to max

Devices	Stock	Medius	Result
The 44 devices both boxes clone	0.68-1.50 s	0.78-2.40 s	Equal

Poll interval

How often the PC polls each clone, against the native interval.

Interval the PC polls at

Device	Stock	Medius	Result
Four mice with a 10 ms intervalIncluding a two-mouse device and a mouse with two configurations	1 ms	Native interval	MediusStock defect
Mouse with an 8 ms interval	1 ms	Native interval	MediusStock defect
Mouse with a 4 ms interval	1 ms	Native interval	MediusStock defect
Mouse with a 2 ms interval	1 ms	Native interval	MediusStock defect
Mouse with a 10 ms interval and a 1,500-byte report descriptor	Native interval	Native interval	Equal
Vendor HID interface with a 4 ms interval	Native interval	Native interval	Equal
XInput pad with 2-64 ms intervals	Native interval	Native interval	Equal

Reports/s reaching the PC

Device	Stock	Medius	Result
Mouse reporting every 1 ms with a 10 ms intervalNative rate: 125/s	Above native rate	Native rate	MediusStock defect
Mouse reporting every 8 ms with an 8 ms interval	Native rate	Native rate	Equal

Interval the clone declares for a high-speed mouse

Device	Stock	Medius	Result
High-speed mouse declaring bInterval 4 (1 ms at high speed)Both clones run at full speed, where the PC reads bInterval 4 as 4 ms	1 ms	Native bInterval 4	Differs

Medius with imperfect clones on

The devices Medius refuses as it ships, given to it again with imperfect clones on. Stock has no such setting, so its column repeats the results above.

Native data reaching the PC

Device	Stock	Medius	Result
Wooting 60HE+	An interface sends nothing	All data arrives	Medius
Mouse claiming a 3,000-byte report descriptorIt sends 50 bytes, which the PC pads to 3,000 with zeros	All data arrives	All data arrives	Equal
Mouse with an unused second configuration	All data arrives	All data arrives	Equal

Clone faithfulness

Device	Stock	Medius	Result
Vendor interface with an isochronous endpoint	Faithful	Faithful	Equal
Two devices with a bulk endpoint	Faithful	Faithful	Equal
Mouse with a vendor interface, five IN endpoints	Faithful	Faithful	Equal
Mouse with a vendor interface, six IN endpoints	Imperfect	Faithful	Medius
Wooting 60HE+	Faithful	Faithful	Equal
Mouse claiming a 3,000-byte report descriptorIt sends 50 bytes, which the PC pads to 3,000 with zeros	Faithful	Faithful	Equal
Mouse with an unused second configuration	Imperfect	Faithful	Medius

Data through every endpoint

Each device streams a counter on every IN endpoint in turn, at its declared rate. The PC reads each endpoint through usbfs with eight transfers queued. A cloned endpoint delivering <95% of the native rate counts as sending nothing. Medius as it ships, imperfect clones off.

Endpoints delivering

Device	Stock	Medius	Result
Vendor interrupt IN	Every endpoint at the native rate	Every endpoint at the native rate	Equal
Vendor IN numbered 0x84	Every endpoint at the native rate	Every endpoint at the native rate	Equal
Vendor IN numbered 0x85	Every endpoint at the native rate	Every endpoint at the native rate	Equal
Vendor IN numbered 0x86	Every endpoint at the native rate	Every endpoint at the native rate	Equal
Vendor IN numbered 0x87	An endpoint sends nothing	Not cloned	Medius
Vendor IN in an alternate setting	Every endpoint at the native rate	Every endpoint at the native rate	Equal
CDC notification endpoint	Every endpoint at the native rate	Every endpoint at the native rate	Equal
HID interface with two INs	Every endpoint at the native rate	Every endpoint at the native rate	Equal
Vendor bulk IN numbered 0x85	Every endpoint at the native rate	Not cloned	Stock
HID interface with a bulk IN	Every endpoint at the native rate	Not cloned	Stock
Vendor bulk pair	Every endpoint at the native rate	Not cloned	Stock
HID IN declaring 65 bytes	An endpoint sends nothing	Not cloned	Medius
Two high-numbered INs beside a mouse	Every endpoint at the native rate	Every endpoint at the native rate	Equal
Mouse with a vendor interface, five INs	An endpoint sends nothing	Not cloned	Medius
Mouse with a vendor interface, six INs	An endpoint sends nothing	Not cloned	Medius
Ten interfaces	Every endpoint at the native rate	Every endpoint at the native rate	Equal
Vendor interface numbered 12	Every endpoint at the native rate	Every endpoint at the native rate	Equal
XInput pad, four INs	Every endpoint at the native rate	Every endpoint at the native rate	Equal
Wooting 60HE+, five INs	An endpoint sends nothing	Not cloned	Medius

Endpoints delivering, Medius with imperfect clones on

Large report descriptors

A mouse with its report descriptor padded to 256-2,047 bytes.

HID driver on the PC

Report descriptor	Stock	Medius	Result
256 or 512 bytes	Loads	Loads	Equal
513-700 bytes	Doesn't load	Loads	Medius
768-2,047 bytes	Doesn't load	Loads	MediusStock defect

Endpoint 0 replies

The PC sent standard, class and vendor requests to each clone, and each reply was checked against the native reply. Reply times aren't ranked: a faithful clone matches the native reply time, which isn't measured.

Reply the PC gets

Request	Stock	Medius	Result
Device descriptor	Native reply	Native reply	Equal
Configuration descriptor	Native reply	Native reply	Equal
String descriptors	Native reply	Native reply	Equal
Descriptors the real device doesn't have	Native reply	Native reply	Equal
HID report descriptor	Native reply	Native reply	Equal
HID class descriptor	STALL	Native reply	MediusStock defect
GET_STATUS, GET_CONFIGURATION and GET_INTERFACE	Native reply	Native reply	Equal
Feature report 3	Native reply	Native reply	Equal
Vendor requests	Native reply	Native reply	Equal

Reply time on the bus

Request	Stock	Medius
Device descriptor	597-610 µs	123 µs
Configuration descriptorAll 34 bytes	772-787 µs	160 µs
Product string	634-636 µs	161-162 µs
HID report descriptor	794 µs	208-210 µs
String the real device doesn't have	556-570 µs	378-381 µs
GET_STATUS	574 µs	122-123 µs
Feature report 3	575-577 µs	344-345 µs
Vendor request 0x42	598-599 µs	462-464 µs