At 01:22 PM 7/10/2007, Rial Juan wrote:
>Bus 007 Device 003: ID 0c45:624e Microdia
>Device Descriptor:
> bLength 18
> bDescriptorType 1
> bcdUSB 2.00
> bDeviceClass 0 (Defined at Interface level)
> bDeviceSubClass 0
> bDeviceProtocol 0
> bMaxPacketSize0 64
> idVendor 0x0c45 Microdia
> idProduct 0x624e
>
snip
> Interface Descriptor:
> bLength 9
> bDescriptorType 4
> bInterfaceNumber 0
> bAlternateSetting 8
> bNumEndpoints 3
> bInterfaceClass 255 Vendor Specific Class
> bInterfaceSubClass 255 Vendor Specific Subclass
> bInterfaceProtocol 255 Vendor Specific Protocol
> iInterface 0
> Endpoint Descriptor:
> bLength 7
> bDescriptorType 5
> bEndpointAddress 0x81 EP 1 IN
> bmAttributes 1
> Transfer Type Isochronous
> Synch Type None
> Usage Type Data
> wMaxPacketSize 0x1400 3x 0 bytes
> bInterval 1
I don't know who the maintainer for lsusb is, but the above ep
descriptor decode is kind of confusing. I am testing high speed, high
bandwidth iso/in endpoints (from a FX2 device side) and noticed this
in my 2.6.20.15 ubuntu system. The problem would seem to be that
lsusb is using the usb 1.1 max packet size of 1023 (0x3ff) as a mask
for the endpoint size. Really it should use 0x7ff as a mask as
described in the usb 2.0 doc, then it will work clearly for both usb
1.0 and 2.0. If it did that it would show:
wMaxPacketSize 0x1400 3x 1024 bytes
Regards, Steve
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