On 06/16/2015 05:32 PM, Ian Jackson wrote: > I have just discovered that the value used in /dev/disk/by-path is not > from sysfs, or at least, not directly. > > udev cobbles it together with a bunch of string mangling, from > information mostly from sysfs. There is no corresponding thing for > usb devices. > > So Linux, the kernel, does not actually provide a stable device name > string. This is obviously absurd, but I think fixing it is out of > scope. > > I suggest we provide a facility to allow a user to specify a fnmatch > glob pattern to be applied to the sysfs path. That way when they see > their device is > /devices/pci0000:00/0000:00:1d.7/usb1/1-1 > they can write > /devices/pci0000:00/0000:00:1d.7/usb*/*-1 > which will match exactly and only the right thing.
What about Juergen's system that has two usbN directories in a single pci node? Quoting: --- Hmm, perhaps. On my system I've got: /sys/devices/pci0000:00/0000:00:14.0/usb3/ /sys/devices/pci0000:00/0000:00:14.0/usb4/ So two busses on one pci bus address. Are usb3 and usb4 always in this order or are they sometimes just numbered the other way round? --- Assuming that usb3 and usb4 are actually distinct busses, and they might both have something plugged into port; in which case a glob like this: devices/pci0000:00/0000:00:14.0/usb*/*-1 Might match both of the following: /sys/devices/pci0000:00/0000:00:14.0/usb3/3-1 /sys/devices/pci0000:00/0000:00:14.0/usb4/4-1 -George _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
