On Wed, 20 Nov 2013, Kumar Gokhare wrote: > Hello, > > I hope this is the right place to query, if not I apologize. > > I have an android device which runs 2.6.32 kernel(v. old) which > randomly disconnects all downstream devices from the single usb port > occasionally. The issue seems to start from ehci reporting a power > change event as in the below logs, I was hoping to make sense of what > the below logs mean (especially first couple of lines) and some > direction as to how to debug this issue. It looks like some sort of > electrical/hardware issue but ill let the experts comment on it. > > The device 1-0:1.0 seem to be an interrupt ep of Tegra ehci. There is > a Genesys Logic controller hub connected to the usb port. > > Thanks in advance for any pointers. > > <7>[ 1493.733165] hub 1-0:1.0: state 7 ports 1 chg 0000 evt 0002 > <7>[ 1493.733245] tegra-ehci tegra-ehci.2: GetStatus port 1 status > c00100a POWER sig=se0 PEC CSC > <7>[ 1493.733297] hub 1-0:1.0: port 1, status 0100, change 0003, 12 Mb/s > <6>[ 1493.733329] usb 1-1: USB disconnect, address 2 This isn't a power-change event. It's just an ordinary disconnect, the same as you'd get if you unplugged the Genesys Logic hub by hand. It could be caused by a bad electrical connection or by a hardware bug. 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
