> > AFAICT, all we need to do is add SA_SAMPLE_RANDOM to the request_irq call > > flags in the host controllers. > > I think most controllers interrupt every frame.
UHCI sends a more regular stream of interrupts, since it needs the software to tend things rather often. OHCI and EHCI tend to use interrupts only when transfers complete. > That would be a very poor source of entropy. The entropy comes from unpredictabillity, which is more a function of the USB devices rather than the controller. So keyboard and mouse code (device level) is a more appropriate place to track entropy than HCDs (controller level). Consider video-over-usb: highly regular interrupt pattern, no matter what controller is in use. Yet ... if you point the video at a (powered-up) Lava Lamp, the _image_ will be a rather good source of entropy. (And patented by SGI as I recall.) Oliver's suggestion of device connect/disconnect calls might be worth looking at. While the interrupts themselves are known to occur at N frame boundaries, not every frame will have such an interrupt. Much like USB keyboards/mice. - Dave _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
