bug#28695: 26.0.60; Rendering lag spikes caused by double-buffering on Linux

[Eli Zaretskii]

> From: Bryan Gilbert <bryan@bryan.sh>
> Date: Tue, 03 Oct 2017 23:10:16 -0400
> 
> Step number 3 is a bit of a messy step, however by lowering the minimum
> query size from 3 characters to 1 character makes the rendering lag spikes
> painfully obvious.

Thanks for the report.

While we are waiting for the double-buffering issues to be looked at,
you should be able to work around this problem by using the following
snippet from NEWS:

  If your system has [the XDBE] extension, but an
  Emacs built with double buffering misbehaves on some displays you use,
  you can disable the feature by adding

    '(inhibit-double-buffering . t)

  to default-frame-alist.  Or inject this parameter into the selected
  frame by evaluating this form:

    (modify-frame-parameters nil '((inhibit-double-buffering . t)))