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

[Xiaofan C. <xia...@gm...>]

On Mon, Apr 27, 2009 at 7:03 AM, Francisco Escarpa
<pac...@gm...> wrote:
>
> 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.
>
> Apr 27 00:03:07 sol kernel: usb 6-9.4: new high speed USB device using
> ehci_hcd and address 14
> Apr 27 00:03:07 sol kernel: usb 6-9.4: config 1 interface 0 altsetting 0
> bulk endpoint 0x1 has invalid maxpacket 64
> Apr 27 00:03:07 sol kernel: usb 6-9.4: config 1 interface 0 altsetting 0
> bulk endpoint 0x82 has invalid maxpacket 1024
> Apr 27 00:03:07 sol kernel: usb 6-9.4: configuration #1 chosen from 1 choice
> Apr 27 00:03:07 sol kernel: usb 6-9.4: New USB device found, idVendor=0547,
> idProduct=1002

As far as I know the firmware is not compliant to USB 2.0 specifications.
The fact that it is working under device does not change that fact. In fact,
you should try to see if it works under Windows Vista which follows USB
standard better than XP. You can also try USBCV Chapter 9 test on this
device and see if it can pass.

Quote from Chapter 5.8.3 of USB 2.0 Specification from usb.org.
"All Host Controllers are required to have support for 8-, 16-, 32-, and
64-byte maximum packet sizes for full-speed bulk endpoints and 512
bytes for high-speed bulk endpoints. No Host Controller is required to
support larger or smaller maximum packet sizes."

So the max packet size of 64 and 1024 are both illegal for your high
speed device.

Luckily you are using Linux and the Linux USB kernel developers
(some are on this list) should be able to help you to use a quirk
or things like that to support your device.

-- 
Xiaofan http://mcuee.blogspot.com