usb hub problems

[Erwin Rol]

I have a USB webcam and that now works with the normal kernel pwc
driver. I noticed a strange problem, since I got to many USB devices I
got a hub and at that point my webcam disappeared. It seems when it is
connected to the HUB ekiga can not use it, it doesn't show up in the
settings. When i directly connect it to my computer it does work. In
both cases the kernel reports the new /dev/video0 so it does see the
device. 

this is what the USB bus looks like with the HUB 

Bus 004 Device 021: ID 046d:08b2 Logitech, Inc. QuickCam Pro 4000
Bus 004 Device 010: ID 046d:c501 Logitech, Inc. Cordless Mouse Receiver
Bus 004 Device 005: ID 0731:0528 Susteen, Inc. SonyEricsson DCU-11 Cable
Bus 004 Device 004: ID 03f0:0317 Hewlett-Packard LaserJet 1200
Bus 004 Device 002: ID 04b4:6560 Cypress Semiconductor Corp. CY7C65640
USB-2.0 "TetraHub"
Bus 004 Device 001: ID 0000:0000  
Bus 003 Device 001: ID 0000:0000  
Bus 002 Device 001: ID 0000:0000  
Bus 001 Device 001: ID 0000:0000  

when I unplug the webcam and replug it logs show;

Jul 29 22:57:35 xpc kernel: usb 4-1.3: new full speed USB device using ehci_hcd and address 22
Jul 29 22:57:35 xpc kernel: usb 4-1.3: configuration #1 chosen from 1 choice
Jul 29 22:57:35 xpc kernel: pwc: Logitech QuickCam 4000 Pro USB webcam detected.
Jul 29 22:57:35 xpc kernel: pwc: Registered as /dev/video0.

When I now start ekiga it doesn't find the webcam and I get the
following messages in my log file;

Jul 29 22:59:31 xpc kernel: pwc: Failed to set video mode VGA at 30 fps; return code = -22
Jul 29 22:59:31 xpc kernel: pwc: Failed to set video mode QSIF at 10 fps; return code = -32
Jul 29 22:59:31 xpc kernel: pwc: Failed to set video mode VGA at 30 fps; return code = -22
Jul 29 22:59:31 xpc kernel: pwc: Failed to set video mode QSIF at 10 fps; return code = -32
Jul 29 22:59:31 xpc kernel: pwc: Failed to set video mode VGA at 30 fps; return code = -22
Jul 29 22:59:31 xpc kernel: pwc: Failed to set video mode QSIF at 10 fps; return code = -32
Jul 29 22:59:31 xpc kernel: pwc: Failed to set video mode VGA at 30 fps; return code = -22
Jul 29 22:59:31 xpc kernel: pwc: Failed to set video mode QSIF at 10 fps; return code = -32
Jul 29 22:59:31 xpc kernel: pwc: Failed to set video mode VGA at 30 fps; return code = -22
Jul 29 22:59:31 xpc kernel: pwc: Failed to set video mode QSIF at 10 fps; return code = -32
Jul 29 22:59:33 xpc kernel: pwc: Failed to set video mode VGA at 30 fps; return code = -22
Jul 29 22:59:33 xpc kernel: pwc: Failed to set video mode QSIF at 10 fps; return code = -32
Jul 29 22:59:33 xpc kernel: pwc: Failed to set video mode VGA at 30 fps; return code = -22
Jul 29 22:59:33 xpc kernel: pwc: Failed to set video mode QSIF at 10 fps; return code = -32
Jul 29 22:59:33 xpc kernel: pwc: Failed to set video mode VGA at 30 fps; return code = -22
Jul 29 22:59:33 xpc kernel: pwc: Failed to set video mode QSIF at 10 fps; return code = -32

When I now plug it directly into my computer i see the following in the log file;

Jul 29 23:01:09 xpc kernel: usb 4-1.3: USB disconnect, address 22
Jul 29 23:01:13 xpc kernel: ohci_hcd 0000:00:1c.0: wakeup
Jul 29 23:01:13 xpc kernel: usb 1-3: new full speed USB device using ohci_hcd and address 6
Jul 29 23:01:15 xpc kernel: usb 1-3: configuration #1 chosen from 1 choice
Jul 29 23:01:15 xpc kernel: pwc: Logitech QuickCam 4000 Pro USB webcam detected.
Jul 29 23:01:15 xpc kernel: pwc: Registered as /dev/video0.

Notice the difference that it now reports it is using _O_hci_hcd instead
of _E_hci_hcd. When I now start ekiga it finds the webcam and it works,
and the log files show the following;

Jul 29 23:04:12 xpc kernel: pwc: Failed to set video mode VGA at 30 fps; return code = -22

I had the same problem with my HP-scanner, it worked when it was
directly connected to the computer but could not be found when connected
to the hub. the other devices like my mouse, printer, phone work just
fine. I tried the HUB with and without external power supply and with
other devices on it and just the webcam on it, and the results are the
same, when connected to the hub the webcam doesn't work.

Any idea what the problem could be ?

TIA,

Erwin