On Thursday 21 May 2020 14:13:29 David Wright wrote:

> On Thu 21 May 2020 at 13:02:49 (-0400), Gene Heskett wrote:
> > On Thursday 21 May 2020 10:10:10 to...@tuxteam.de wrote:
> > > On Thu, May 21, 2020 at 08:23:55AM -0400, Gene Heskett wrote:
> > > > Since updating to stretch, udev has been randomly swapping
> > > > ttyUSB0 and ttyUSB1 and sometimes ttyUSB2 around, confusing the
> > > > hell out of heyu, a trs-80-coco3, and occasionally even nut. 
> > > > Nut (apc ups) is not on a usb-serial adapter, it just a usb
> > > > cable but the other 2 are on individually unique FTDI adaptors.
> > > >
> > > > What udev persistent file, and where is it, do I edit and chattr
> > > > +i to effect a permanent cure for this apparently random device
> > > > renaming?
> > >
> > > I don't know about this one -- but note that the files in /etc
> > > (i.e. /etc/udev/rules.d) are yours to play with and override the
> > > distro's, which are in /lib/udev/rules.d. So you shouldn't (TM)
> > > muck around with chattr.
> >
> > IOW, and what the man pages keep secret, I should cp
> > the /lib/udev/rules.d stuff I need to /etc/udev/rules.d and edit
> > that.
>
> That's one way of doing it. The other is to use /lib/udev/…
> as examples to make it easier to understand the man page
> (there's no secret).
>
> > I wasn't sure which was which, thank you.
> >
> > > > And whats the command to restart udev from a clean slate without
> > > > rebooting?
> > >
> > > I don't know by heart, but something with udevadm (perhaps
> > > 'udevadm trigger'). Probably you need an 'udevadm control reload'
> > > for udev to see the changes you made to its configuration.
> > >
> > > Also possibly useful are 'udevadm monitor' and 'udevadm test'.
> > >
> > > My hunch is that the rules which recognize your USB adapters
> > > have somehow changed and that it can't reliably distinguish
> > > among the individual fobs.
> >
> > They have not been touched since stretch was installed about 9
> > months back and I have been trying to keep ahead of udev by editing
> > conf files ever since.  But you have to do that by guess and by
> > golly cuz udev increments the name if you pull the cable and
> > reinsert it just to get an ID of which one it is from dmesg.  So you
> > wind up chaseing your tail until it catches you, at one point 2
> > years ago on a diff mobo I was running heyu on ttyUSB14, with only 2
> > ttyUSB's in the cage.  Why the heck can it not reuse a vacated
> > device number?  Boggles what little mind I have left.
> > […]
> > I have no clue why its even named persistent when in 2 Asus
> > motherboards and 12 years with the weeping willow I have for a usb
> > tree here, it has never assigned the same usb socket the same
> > ttyUSB# in a row during bootup.  We were far better off when they
> > were assigned in the order found & things only got scrambled if you
> > scrambled the cables plugging them back in after the systems annual
> > D&C.
>
> So you have to write a list with the order of plugging in, and stick
> that to the back of the computer? And every time you reboot, you have
> to unplug everything first to prevent a race? No, thank you.
>
> > Thanks for the info, maybe, hopefully I can make it persistent now.
> > Maybe. usb-devices does give me the unique stuff, but udevadm does
> > not.
>
> Why would you use usb-devices? You have to run it and then search
> through the list it returns. Whereas udevadm comes to you whenever
> something changes, tells you what, and gives you all the information
> you need as event properties.
>
If you run it with the right options. Now I know how but my editing foo 
is burned out for today. Tommorrow before a big box of parts arrive I 
should arrive at working code.  Thanks and stay well David.

> Cheers,
> David.


Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/gene>

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