Re: [Libusb-devel] Problem with libusb_0.7, cypress fx2LP and linux

[<ti...@pr...>]

On Mon, Apr 27, 2009 at 01:03:31AM +0200, Francisco Escarpa wrote:
> 
> I', trying to interface with an astronomic camera (still image, long
> exposure) based on Micron MT9M001 and cypress cy7c68013, on Opensuse
> 11.1(X86-64)
> 
> The manufacturer provided me with the firmware. As soon I plug the device, I
> load the firmware with fxload, and then the camera is reset. I got some
> error messages about invalid maxpacket.

Did you actually buy this as a finished product?  If so, this manufacturer 
is deserving of a lawsuit.

> lsusb provided no abnormal data (as far I see):
> 
> Bus 006 Device 014: ID 0547:1002 Anchor Chips, Inc. Python2 WDM Encoder
> Device Descriptor:
>   bLength                18
>   bDescriptorType         1
>   bcdUSB               2.00
>   bDeviceClass            0 (Defined at Interface level)
>   bDeviceSubClass         0
>   bDeviceProtocol         0
>   bMaxPacketSize0        64
>   idVendor           0x0547 Anchor Chips, Inc.
>   idProduct          0x1002 Python2 WDM Encoder
>   bcdDevice            0.00
>   iManufacturer           1 Cypress
>   iProduct                2 EZ-USB FX2
>   iSerial                 0

0547/1002 is the VID/PID exposed by an unconfigured FX2.  It is a number
that belongs to Cypress.  Manufacturers are SPECIFICALLY PROHIBITED by
the Cypress license to release products that use this number.  They are 
supposed to change it to their own ID numbers.  It's not hard to do.

>   bNumConfigurations      1
>   Configuration Descriptor:
>     bLength                 9
>     bDescriptorType         2
>     wTotalLength           32
>     bNumInterfaces          1
>     bConfigurationValue     1
>     iConfiguration          0
>     bmAttributes         0x80
>       (Bus Powered)
>     MaxPower              100mA
>     Interface Descriptor:
>       bLength                 9
>       bDescriptorType         4
>       bInterfaceNumber        0
>       bAlternateSetting       0
>       bNumEndpoints           2
>       bInterfaceClass       255 Vendor Specific Class
>       bInterfaceSubClass      0
>       bInterfaceProtocol      0
>       iInterface              0
>       Endpoint Descriptor:
>         bLength                 7
>         bDescriptorType         5
>         bEndpointAddress     0x01  EP 1 OUT
>         bmAttributes            2
>           Transfer Type            Bulk
>           Synch Type               None
>           Usage Type               Data
>         wMaxPacketSize     0x0040  1x 64 bytes
>         bInterval               0

That's invalid.  A bulk endpoint in a high-speed device MUST have a 
max packet size of 512.  There is no other choice.

>       Endpoint Descriptor:
>         bLength                 7
>         bDescriptorType         5
>         bEndpointAddress     0x82  EP 2 IN
>         bmAttributes            2
>           Transfer Type            Bulk
>           Synch Type               None
>           Usage Type               Data
>         wMaxPacketSize     0x0400  1x 1024 bytes
>         bInterval               0

This ALSO is invalid.  You can't use 64, and you can't use 1024.  The 
ONLY valid choice for a bulk endpoint is 512.  The 64-byte endpoint 
might be made to work, but 1024 certainly cannot.

Also, there are no alternate settings in these descriptors.  If there are
supposed to be alternate settings, then my guess is that your firmware
load did not work.
-- 
Tim Roberts, ti...@pr...
Providenza & Boeklheide, Inc.