On Mon, 5 Oct 2015, Eugen Rogoza wrote: > Hello, > > in xHCI mode I'm experiencing random disconnects and reconnects of my ASMedia > ASM1051-based external HDD enclosure. > > The only combination where the disconnects are happening is Intel USB Host > Controller + Linux kernel + XHCI mode (see further observations below). > > I did some tracing with libpcap (can be opened in Wireshark). I did one trace > on the NEC chipset where I have no disconnects and one on the Intel chipset > where I do experience disconnects. The Intel output clearly shows that at > some point in time a URB_INTERRUPT is sent from "1.1" (I suppose it is the > hub) to the host (packet 1780) and the host requests a port reset (packet > 1800). The procedure repeats after a random time (packet 3648). The NEC trace > does not have such interrupts. > > Why is that interrupt sent? Where is it coming from?
It comes from the xHCI host controller. It is an indication that the link to the device became inactive, possibly as a result of Link Power Management. > Additional info and observations below: > > Observations: > > - independent of activity/workload Are you sure about that? In your Intel pcap file, the problem occurred only after long periods of inactivity: 40 seconds the first time, 150 seconds the second time. > - works perfectly under Windows 7 in XHCI mode > - works everywhere (Linux and Windows) when using USB 2.0 mode (EHCI) > - tried with kernels 4.0.5, 4.2.0 and 3.18.16 - no difference > - enabling/disabling runtime PM and USB power management doesn't make any > difference The only way to turn off Link Power Management currently is to disable CONFIG_PM entirely. > - works on a different host hardware with a NEC USB3.0 host controller (see > details below). Tested with kernel 3.17.7. > > Traces can be downloaded here: > > http://wikisend.com/download/136936/usb3_intel.pcapng.gz > http://wikisend.com/download/612580/usb3_nec.pcapng.gz > > > Output of /var/log/messages demonstrating the issue: > http://pastebin.com/wbUr5mMe > > > lsusb and lspci outputs (Intel hardware): http://pastebin.com/XDEz2x2g > > > lsusb and lspci outputs (NEC hardware): http://pastebin.com/1M1ZVyJr > > > Thanks for help, Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
