On Sun, 29 Jul 2012, James wrote: > >> It noticeably slows down booting. > > > > It shouldn't interfere appreciably with booting, unless you're waiting > > for some other USB device to be detected. All the USB communication > > should happen in the background. > > It does wait until the UPS is stable, I don't know why. I don't know why either. > > If you want to get more information about what's happening, you can use > > usbmon to record the communications when the UPS is plugged in (see > > Documentation/usb/usbmon.txt for instructions). > > I read the document but I didn't see any way to turn it on while the OS is booting. No, there's no way to do that, unfortunately. > My UPS only has one disconnect/connect if I unplug/plug in the cable > after the OS is done booting. In your previous email these was an example with more than one. > Maybe the UPS is trying to do something and the USB system is not > fully initialized. I doubt that very much. More likely something is wrong with the UPS. One possibility is that the problem arises because on your system, ohci-hcd is loaded before ehci-hcd. Normally this doesn't matter, but perhaps your UPS is sensitive to the disruption that occurs when the EHCI controller takes over the port and then hands it back to the OHCI controller. In fact, there ought to be a message in the log warning about this, somewhere before the start of the extracts you posted. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
