Re: udev alzheimers
On Thursday 21 May 2020 10:10:10 tomas@tuxteam.de wrote:
> On Thu, May 21, 2020 at 08:23:55AM -0400, Gene Heskett wrote:
> > greetings all;
> >
> > 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.
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.
Now it appears I have blown a salt chip in the coco, and they are made
out of pure unobtainium in 2020 as they are now 35+ years old. They were
a custom chip first made in 81 or 82 for Radio shacks color computer
line. Analogue portions of it have been bypassed 25 years already, looks
like its logic has now died too. 2nd time.
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.
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.
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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