Bug#761671: Not just keypress: terminal output, and mouse events too

[Conrad Hughes]

I can confirm this.  It makes Gnome unusable if you're a text terminal
type of person.  That said, I think it may be deeper than
gnome-terminal, but you'll be a better judge of that.

I first encountered this issue after dist-upgrading to jessie at the
start of September.  Symptoms:

  - Input events appear to be processed only on receipt of the next
    event, so if you type ['d', 'e', backspace, 'f', space], you'll see
    the following:

    - After d: [nothing]
    - After e: d
    - After backspace: de
    - After f: d
    - After space: df

  - Interactions with mouse clicks throughout the GUI suffered the same
    problem.

  - Terminal output suffers interruptions too: for example, you could
    start vim and only half of the first screen of text would be
    displayed.  You'd see the rest after your first keypress.  It
    sometimes even stops half way through terminal control codes, so you
    get a "^[<"-type half-escape sequence, which turns into whatever the
    right things is when you hit the next key.

  - In fact, it's possible that *output* is the sole problem (maybe
    all events are processed immediately, but the consequences just
    aren't shown).  I haven't yet been able to discern whether this is
    the case though; it just occurred to me as a possibility, and I'll
    keep an eye out for evidence now.

Since the computer became completely unusable (imagine using vi in the
above circumstances), I wiped it and tried a fresh install of jessie
from scratch.

Everything seemed good, but of course at that point we were still on
xfce-by-default.  Now with the recent update back to Gnome, the problem
has reappeared, although it is much less frequent: it doesn't happen
*all the time* (which was the case in September; now it happens in fits
every hundred keypresses), and I haven't witnessed mouse problems yet,
but I only started using the - um - upgrade this morning.

In fact, since I'd been using xfce-terminal when I first logged back in
under Gnome, I first witnessed its reappearance while using
xfce-terminal under Gnome, not gnome-terminal - having switched to
gnome-terminal the problem is visible in both.  This is why I suggest
above that the problem may be deeper than gnome-terminal.

I've tried swapping between USB and PS/2 keyboards, and that doesn't
affect the problem.  No sign of it either in the pure xfce environment.

I'd be very grateful for any help, as this pretty much stops me from
being able to use jessie at all.

Best regards,
Conrad