Re: usb snooper
On Wednesday 27 November 2019 12:50:37 Gene Heskett wrote:
> On Wednesday 27 November 2019 08:41:38 tomas@tuxteam.de wrote:
> > On Wed, Nov 27, 2019 at 08:22:25AM -0500, Gene Heskett wrote:
> >
> > [...]
> >
> > > Doesn't look as if it will work with this preempt-rt kernel :(
> > >
> > > pi@rpi4:~/linuxcnc/configs/sheldon-lathe $ sudo /usr/sbin/tcpdump
> > > -i 7 tcpdump: Can't open USB bus file /sys/kernel/debug/usbmon/1t:
> > > No such file or directory
> >
> > Throwing the error message into a search engine yields some
> > promising links:
> >
> >
> > https://stackoverflow.com/questions/32740413/no-usb-bus-file-even-af
> >te r-enabling-usbmon-in-android-kernel
> > https://unix.stackexchange.com/questions/546719/no-such-file-or-dire
> >ct ory-sys-kernel-debug-usb-usbmon
> >
> > So it seems you need the usbmon module loaded (is it?)
>
> no, is now. And watching the 3 choices for more than enough time to
> see several of these "noise events" if that what it is, gets this:
> pi@rpi4:~/linuxcnc/configs/sheldon-lathe $ sudo /usr/sbin/tcpdump -i
> 8 tcpdump: verbose output suppressed, use -v or -vv for full protocol
> decode
> listening on usbmon1, link-type USB_LINUX_MMAPPED (USB with padded
> Linux header), capture size 262144 bytes
> 12:07:06.611219 CONTROL SUBMIT to 1:17:0
> 12:07:06.613656 CONTROL COMPLETE from 1:17:0
> 12:07:06.613861 CONTROL SUBMIT to 1:16:0
> 12:07:06.615532 CONTROL COMPLETE from 1:16:0
> 12:07:06.615886 CONTROL SUBMIT to 1:3:0
> 12:07:06.616363 CONTROL COMPLETE from 1:3:0
> 12:07:06.616506 CONTROL SUBMIT to 1:2:0
> 12:07:06.616766 CONTROL COMPLETE from 1:2:0
> 12:07:06.616882 CONTROL SUBMIT to 1:1:0
> 12:07:06.616924 CONTROL COMPLETE from 1:1:0
> ^C
> 10 packets captured
> 10 packets received by filter
> 0 packets dropped by kernel
> pi@rpi4:~/linuxcnc/configs/sheldon-lathe $ sudo /usr/sbin/tcpdump -i
> 9 -v
> tcpdump: listening on usbmon2, link-type USB_LINUX_MMAPPED (USB with
> padded Linux header), capture size 262144 bytes
> 12:09:50.820947 CONTROL SUBMIT to 2:3:0
> 12:09:50.821114 CONTROL COMPLETE from 2:3:0
> 12:09:50.821365 CONTROL SUBMIT to 2:2:0
> 12:09:50.821512 CONTROL COMPLETE from 2:2:0
> 12:09:50.821699 CONTROL SUBMIT to 2:1:0
> 12:09:50.821737 CONTROL COMPLETE from 2:1:0
> ^C
> 6 packets captured
> 6 packets received by filter
> 0 packets dropped by kernel
> pi@rpi4:~/linuxcnc/configs/sheldon-lathe $ sudo /usr/sbin/tcpdump -i
> 10 -vv
> tcpdump: listening on usbmon3, link-type USB_LINUX_MMAPPED (USB with
> padded Linux header), capture size 262144 bytes
> 12:10:46.640549 CONTROL SUBMIT to 3:1:0
> 12:10:46.640597 CONTROL COMPLETE from 3:1:0
> ^C
> 2 packets captured
> 2 packets received by filter
> 0 packets dropped by kernel
> pi@rpi4:~/linuxcnc/configs/sheldon-lathe $
>
> > and
> > the debugfs pseudo file system mounted (again, is it?).
>
> No. Each of the above captures was presented within 2 secs of the
> invocation, followed by silence, so I get the impression I'm barking
> up the wrong tree and should look elsewhere for the cause of the
> motion stutter. This app, linuxcnc, has an o-scope like facility with
> very limited sampling to aid in signal tracing, limited because it
> only runs once per thread invocation, and since I am useing Mesa fpga
> based interface cards which take over the need for 20 microsecond
> controls, the remaining thread invoc's are at 1ms or even 5ms
> intervals for the jog dials I've installed to replace the manual
> cranks it had 70 years ago. Those signals I can see, but the manual
> signals, like from the arrow keys on the keyboard, are all hidden, not
> available to be seen by this "scope", going thru a bunch of steering
> stuff before getting to the actual joint circuitry as a move a motor
> command.
>
> The app itself has an 8 digit debug control, but I haven't found a
> definition of which of those 32 bits enables what debugging traces.
> We have several Docs, the main one being over 800 pages, so I have
> some concentrated reading to do.
>
> Thanks muchly for the help Reco, its appreciated, a lot. I think it
> pretty much rules out local rfi as a source of this problem so I must
> figure out how to look elsewhere.
>
> > HTH
> > -- tomás
>
And I see I'm replying to two helpers, my apologies, Tomas, for leaving
out your contribution, thank you, a bunch.
> Cheers, Gene Heskett
Cheers, Gene Heskett
--
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