Hi,

I've discovered a problem with this device. Wonder if anyone can shed some
light.

It conforms to the CDC ACM so should work with the umodem driver but
initially I got a device error.

What was happening was this:
1. USB driver reads first eight bytes of device descriptor and sees
maxpacket size of 64
2. Sets maxpacket size of 64 in default control pipe endpoint and tries to
read full device descriptor (18 bytes)
3. This gives an UNDERRUN presumably because the data is coming back in 8
byte packets still.
Hence the device error.

I did a hack so that it sets the max packet size after reading the full
device descriptor and now it works fine.

However I'm concerned because I've read section 5.5.3 of the USB spec and it
seems to me that the code was right in the first place and the device was
behaving wrongly.

Any ideas?

Peter Burnett
peterbu@bemac.com