I compile 30 rc7 kernel with usb debugging ON. attaching dmesg output. On Sat, May 30, 2009 at 1:43 AM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > 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 > > -- Regards Jithin Emmanuel http://spotm.in George Bernard Shaw - "A government that robs Peter to pay Paul can always depend on the support of Paul." - http://www.brainyquote.com/quotes/authors/g/george_bernard_shaw.html
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