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[Bug 1499416] Re: xterm freeze when accepting input from usb scanner


Reading the manual, I see that the DS4208 is talking via RS-232, which would make xterm's
role in this mostly as a bystander, since (unless you've made your keyboard the serial device,
it would only be echoing something).

The -l option doesn't show me much either, except for your shell prompt (which looks a
little odd with the doubled ^G and the tilde).  Perhaps if you had added that as an attachment,
I could see better what it's recording.  However, what that records is a little downstream of
the actual input -- it's possible that something is lost in the story.  As I noted, the usual problem
is due to some incomplete control sequence, for which there are documented workarounds.

"accepting input as root" raises the possibility that your shell prompt isn't the same, and
that there's something amiss there.  A "typescript" from "script" (as an attachment) would
show what is sent to the terminal, and is helpful in spotting broken control sequences.

Capturing all of the input sent from the scanner is harder, since that's received in xterm
as a series of X events - which are processed into characters.

There are perhaps better ways to trace this, but generally  I build xterm with a debugging
trace, which would show all of the input events.

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  xterm freeze when accepting input from usb scanner

Status in xterm package in Ubuntu:

Bug description:
  I have a symbol DS4208 Wired USB barcode scanner hooked up to a
  machine running Ubuntu 14.04 via a USB connector.  When using xterm
  and attempting to scan a 1D or 2D barcode the xterm window will accept
  in a couple characters from the USB scanner not in the correct order,
  and then lockup. The number of characters accepted varies, and is
  never in the correct order.

  This also happens from any child process launched from the xterm

  This issue is not present when I first sudo -s to obtain a root shell.
  Scans will be interpreted properly and characters are entered into
  child processes, or command line correctly depending on where the
  cursor is situated.

  This issue is not present in other terminal emulators such as

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