USB Descriptors returning different results on different laptops.

[jeffrey wedekind]

We have a strange issue with the HID class, the USB Descriptors are returning different results on different laptops. Lenovo Think Pad is fine, Dell 5560 is bad. Has anyone seen this issue before? Maybe a MS bug fix or a Dell driver update? Thanks

[Pavel A.]

How exactly you obtain the USB descriptors on Windows? or is that Linux?

[waclawek.jan]

What do you mean by"different results"?

JW​

[jeffrey wedekind]

It is a normal read descriptor from a C# app, on a good PC it's 64 for outputbuffer length and on the bad PC it's 0. Very strange issue

[Tesla DeLorean]

Well DELL ranked a little better than TOSHIBA in terms of broken **** they in-house designed, and installed, and that was perhaps 15 years ago before the latter exited the market. I guess the other problem is that they are prolific, and frequently have remote diagnostic suite installed.

Watch for Hubs and Docking Stations.

Enumerate the entire driver stack establishing drivers/version from the hardware on up.

The 64-byte frame size is perhaps handled differently.

[Pavel A.]

> It is a normal read descriptor from a C# app

Sorry I don't know what the C# app calls ... it could be either the native Windows hid.dll, or some UWP API, or something at USB layer.

Various PC and device vendors can install so called filter drivers that break things. Quality control and testing horribly suck these days. Complain to Dell support or ask in the Microsoft forum here or here (warning: they will need technical details).

[Piranha]

https://en.wikipedia.org/wiki/Host_controller_interface_(USB,_Firewire)#USB

OHCI/UHCI, EHCI and xHCI are standard USB controller interfaces, all of which has a standard drivers in Windows from Microsoft.

Does anyone know what exactly have those manufacturers done? Do they develop and install some "improved" USB controller drivers?

[Pavel A.]

> Does anyone know what exactly have those manufacturers done? Do they develop and install some "improved" USB controller drivers?

AFAIK no, they usually don't install custom host controller drivers since Windows 8.

But filter drivers - definitely yes, and these things can be very invasive. /* for example, a hub filter can "hook" reading of connected device's descriptors, to fix a broken firmware... or ... make a device look totally different */