On 07/29/12 17:36, Alan Stern wrote: > 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 > It doesn't slow my boot anymore but there are 9 disconnect-connects. I changed the port and recompiled the kernel. -- 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
