[cpia] usb errors using cpia/gqcam

[Johannes Erdfelt]

On Wed, Nov 22, 2000, Peter Pregler <Peter_Pregler@email.com> wrote:
> thanx for the info, something to rule out in my debugging. I have got
> a second USB-cam now and tried it out with the latest 2.2.18pre. It
> does work if in the USB-tree the cameras are on different usb-buses
> (0x0553/0x0002 is the camera):
> 
> root@gretel:~# lsusb -t
> Bus#  2
> `-Dev#   1 Vendor 0x0000 Product 0x0000
>   `-Dev#   2 Vendor 0x058f Product 0x9254
>     `-Dev#   3 Vendor 0x0553 Product 0x0002
> Bus#  1
> `-Dev#   1 Vendor 0x0000 Product 0x0000
>   `-Dev#   2 Vendor 0x0553 Product 0x0002
> 
> But is does not work with the cameras on the same buses. The open of
> the second camera fails.
> 
> root@gretel:~# lsusb -t
> Bus#  2
> `-Dev#   1 Vendor 0x0000 Product 0x0000
>   `-Dev#   2 Vendor 0x058f Product 0x9254
>     |-Dev#   3 Vendor 0x0553 Product 0x0002
>     `-Dev#   4 Vendor 0x0553 Product 0x0002
> Bus#  1
> `-Dev#   1 Vendor 0x0000 Product 0x0000
> 
> I have yet to check what is really going on. Do you have any idea?
> How different it the usb-core code in 2.2.18pre and 2.4? Which of the
> usb-uhci drivers is to prefer to see if the problem is cpia or
> usb-core related?

You can't use 2 cpia cameras on the same bus because there isn't enough
bandwidth. The open failing is the USB core telling you that.

It works on 2 busses because each bus has it's own bandwidth.

JE