On Fri, Oct 12, 2007 at 08:01:13AM +0930, Edwards, David (JTS) wrote: > > -----Original Message----- > > From: Nick Guenther [mailto:[EMAIL PROTECTED] > > Sent: Thursday, 11 October 2007 8:01 PM > > To: Edwards, David (JTS) > > Cc: misc@openbsd.org > > Subject: Re: Which remvable drive is connected to which USB port > > > > On 10/11/07, Edwards, David (JTS) > > <[EMAIL PROTECTED]> wrote: > > > Hi again. > > > > > > Just a wrap up to this thread. > > > ----------------- > [snip] > > >> I'm not happy with the fact that the script uses dmesg output. > >> dmesg uses a ring buffer and that can fill very quickly > >> (say if you unplug a usb disk while something is writing > >> to it) which will break the above script totally. However, > >> currently I don't have the time (or probably the expertise) > >> to go through the source to work out a better way to do > >> it. > > > everything in dmesg is also dumped to /var/log/messages. > > disk naming *is* consistent in OpenBSD. devices are all named in a > > deterministic manner, so that they won't change on you without you > > realizing it / adding an extra layer of naming indirection. > > > > What are you actually trying to do here? boot from a USB disk? > > Hi, thanks for responding. > > I'm using USB disks for backups. > > The problem I have is that there are multiple backup sets that > I need to keep for different purposes so I need to know which > physical USB port a disk device is attached to. > > I've got three USB cables labelled with the names of the backup > sets (set 1, set 2...) and when I swap a disk on one of the > cables, I need to know the disk device to mount so that I can > dump the right set onto it.. > > It seems that the disk devices are named (sd1, sd2 etc) based > on which one is plugged in first (unrelated to the physical > port). My testing shows that the disk device names are retained > as long as the box is not rebooted, but if it reboots, then > I can no longer be sure that the right disk is plugged into > the right port and my backup sets would get mixed up. > > So, basically I need a tool where I can start with a physical port > description (seems /dev/usb# "addr #" works) and end with a disk > device (sd#). > > The script I put together works fine, but it relies on dmesg (or > as you suggested /var/log/messages) which grates on my sense of > neatness (or maybe I'm being too precious :-) > > I'll take the time to have a look at the sources one day. I'm > sure it would be possible to write a tool that would be able to > work this out in a better way. Would you have any pointers as > to where to start looking?
I would like there to be some kind of usb tool where you can query interesting properties about the usb device, such as manufacturer and serial number. I think there is some kind of tools in ports, but do not think they can give the needed data... Correction. The usbutil package has got a command usbctl that gives the needed data: # usbctl -f /dev/usb1 -a 2 prints out a "DEVICE descriptor" containing: iManufacturer, iProduct, iSerialNumber BUT... The problem is to map what hotplug/attach sees - sd0 class 2, scsibus1 class0 and umass0 class 0, to /dev/usb1 address 2. Missing is still some way to find out what the kernel device tree looks like - the kernel must know that sd0 is attached to scsibus1 targ 1 lun 0 which is attached to umass0 which is attached to uhub1 port 1. The question is if there is a way of finding that without parsing dmesg. I also can not see how to map uhub1 port 1 to /dev/usb1 address2. > > ciao > dave > --- > Dave Edwards -- / Raimo Niskanen, Erlang/OTP, Ericsson AB
