On Fri, 29 May 2009, Jithin Emmanuel wrote: > Yes when using docking station it fails over to uhci and when not it mostly > uses ehci. I have seen it using even uhci when not in docking station. In a > 2.6.27 kernel I saw it using ehci even with docking station. > > What annoys most is the time taken to appear as ready to mount some times it > takes up to 30 mins. > > But if I connect it during boot it gets detected fast, mostly after login > though it keeps printing those error messages. > > I will check again with other laptops with different kernels. > I checked with 2.6.27 kernel. Its not working. I am getting the same > message printed again and again. If its a problem with the hardware > itself, whcy its working after some 20-30 minutes, ( and sometimes by > uhci). > > I have seen this working with ehci in my box with the docking station. > Things are especially worse when I am in office. Now its almost 2 > hours this message is getting printed still no signs of getting ready > to mount. I do not why why thing are very bad at office and not very > much at home. Differences are A/C and docking station. > It mounted after 4 hours. > One thing I noticed is that, during all these time it was trying > different addresses with ehci_hcd and it mounted in the first try with > uhci_hcd. Obviously your docking station hardware is flaky. Sometimes it works, but it requires a lot of retries. Sometimes it doesn't work. The reason why UHCI works better than EHCI is because it operates at USB 1.1 speed, not USB 2.0. The slower data rate is much more resilient against low-level errors. To get more information about why the retries take so long, build a kernel with CONFIG_USB_DEBUG enabled and post part of the dmesg log showing some of those retries. 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
