Alan Stern wrote: > On Thu, 29 Aug 2013, Martin MOKREJŠ wrote: > >> Alan Stern wrote: >>> On Thu, 29 Aug 2013, Martin MOKREJŠ wrote: >>> >>>> Hi Xenia, >>>> thank you, how about inclusion of the "parent hub" number in the >>>> following message (as of now): >>>> >>>> Parent hub missing LPM exit latency info. Power management will be impacted. >>>> >>>> >>>> >>>> I find it awkward to later on run manually lspci/lsusb to find what is the parent. >>> >>> You don't need to run those programs. >>> >>>> I think I do NOT get these messages when I have pcie_aspm=off whereas when >>>> it is on I get the warning. Why PCIe powersaving affects how USB end devices will >>>> be put to sleep I don't know. But that will be the next step to look into. >>>> First the warning message. And maybe it could be improve even further to include >>>> other relevant capabilities of the "parent" present/missing. ;-) >>>> >>>> >>>> Here are bits from my dmesg: >>> >>>> [ 5.291321] usb 4-2: new SuperSpeed USB device number 2 using xhci_hcd >>>> [ 5.313219] usb 4-2: Parent hub missing LPM exit latency info. Power management will be impacted. >>> >>> Since this device is 4-2, the parent hub is usb4. >> >> Hmm, and it's corresponding PCI device? I know, not always the case but ... > > The correspondence between a USB bus and the controller's PCI device > path is harder to figure out. You can't get it from lspci or lsusb -- > although you can get it (with a little difficulty) from "lsusb -v". > Perhaps the easiest way to do it is simply with ls: > > $ ls -l /sys/bus/usb/devices/usb1 > lrwxrwxrwx 1 root root 0 Aug 29 09:48 /sys/bus/usb/devices/usb1 -> ../../../devices/pci0000:00/0000:00:1d.7/usb1/ > > The 0000:00:1d.7 embedded near the end of the output is the > controller's PCI address. > > Note, however, that the change you asked Ksenia to perform (printing > the parent hub's name) won't give you the PCI device. In your case, > for instance, it would simply print "usb4". You are right but of course I wanted this kind of answer ;), ideally along with the PCI/ASPM/whatever relevant features value why the LPM is not available. Running all lspci/lsusb hours later does not ensure I get the the information how it was configured at that time in the past. -- 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
