Re: [USB IF]Mismatch between EDK2 and a USB vendor

Tian, Feng <feng.tian@...>

Hi, Katayama

We never receive such feedback on inconsecutive usb interface number. I agree EDKII usb driver should be able to handle this.

I am working on a fix, but I have no such device at hand. Could you help me verify it when the patch is ready?

PS: what host controller are you using? EHCI or XHCI?


-----Original Message-----
From: edk2-devel [mailto:edk2-devel-bounces@...] On Behalf Of Yosuke Katayama1
Sent: Wednesday, September 21, 2016 8:05 AM
To: edk2-devel@...
Subject: [edk2] [EDK2][USB IF]Mismatch between EDK2 and a USB vendor


This is relating to my previous post "[edk2] Is this a right place to discuss EDK2's USB IF implementation?"
We found a mismatch between EDK2 source code and our USB vendor's implementation. Could you give us your opinions?

bInterfaceNumber , 9.6.5 Interface from Universal Serial Bus 3.1 Specification Rev 1.0 says;
Number of this interface. Zero-based value identifying the index in the array of concurrent interfaces supported by this configuration.

Regarding this.
EDK2 source code (UsbDesc.c) says:
// If a configuration has several interfaces, these interfaces are
// numbered from zero to n...

The USB vendor says:
* Numbering is not necessarily consecutive * Each interface can be independently turned on/off * Solution allows any combination of interfaces without re-defining the interface number * One general lookup table can tell you what interface is assigned to what interface number.
* For these reasons, the interface definition is like this on our products.
* The interface definition has remained the same from the previous products, and other products before that.
* Current interface numbering is supported by all Microsoft OS * Other PC OEM customers have never raised this issue

As a result, the vendor's USB IF looks like below.

===>Configuration Descriptor<===
bNumInterfaces: 0x02 <<<<
bConfigurationValue: 0x01
iConfiguration: 0x00
bmAttributes: 0xA0 -> Bus Powered
-> Remote Wakeup
===>Interface Descriptor<===
bInterfaceNumber: 0x0C <<<< Interface Number starts from 0x0C instead of 0. [comment from Yosuke]
bAlternateSetting: 0x00
bNumEndpoints: 0x01

===>Interface Descriptor<===
bInterfaceNumber: 0x0D <<<<
bAlternateSetting: 0x00
bNumEndpoints: 0x00

and it hits the following ON_ERROR in UsbDesc.c.
} else if (Setting->Desc.InterfaceNumber >= NumIf) {
DEBUG (( EFI_D_ERROR, "UsbParseConfigDesc: mal-formated interface descriptor\n"));

UsbFreeInterfaceDesc (Setting);
goto ON_ERROR;

What do you think the vendor's implementation?
Also, have you ever had such a USB IF mismatch between EDK2 and USB vendors before? If so, how are you handling such cases in general?

Kind regards,
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