gspca_sq930x: Creative WebCam Live! Pro recognized, kinda initialised but unusable

(Repost from 2013-05-27 14:40:02 GMT, with a better subject line and a new pastebin)

Hello

I'm having trouble with a Creative WebCam Live! Pro, usb id 041e:4038 "Creative Technology, Ltd ORITE CCD Webcam [PC370R]"
This device is supposed to be "supported" but is marked as "untested" at http://gkall.hobby.nl/sq930x.html
Apparently it works up to the point where sq930x fails with this message : gspca_sq930x: reg_r 001f failed -32

See a more complete log here : http://pastebin.com/yY4THaFN

The kernel I'm using is a custom made 3.9.3.
What other information do you need to debug this issue ? What options must I activate in the kernel in order to get a more verbose syslog regarding this component ?
Is there any hope at all for this device, as there seems to be no information available at all from Creative or any other source ?

Sincerely,
 =^.^=