1 files changed, 30 insertions, 0 deletions
diff --git a/guides/setups/operating-systems/debian.org b/guides/setups/operating-systems/debian.org
index cc7bf0e..dc7f5c5 100644
--- a/guides/setups/operating-systems/debian.org
+++ b/guides/setups/operating-systems/debian.org
@@ -394,6 +394,36 @@ had left an error marker somewhere?].  Steps taken:
    (which eventually just writes ~run_im none~ in =~/.xinputrc=).
 
 3. Eventually, maybe I should just uninstall im-config.
+**** random lag
+***** DONE diagnosing
+Since… a few days? weeks? one month? everything randomly becomes
+"choppy":
+
+- typing (Emacs, Terminator, Firefox): I can type in a bunch of words,
+  sit back, wait a few seconds, then watch the words finally write
+  themselves letter by letter.
+- launching programs: ~while time $aprogram ; do sleep 0.5 ; done~,
+  where ~aprogram~ just starts then exits, shows wildly varying times.
+- scrolling a PDF with the touchpad (Evince): the pages stay stuck for
+  a few seconds, then the reader jumps to the new location; the mouse
+  pointer does change during this delay, as text and whitespace
+  (invisibly) scroll by.
+
+I can't remember changing anything recently, nor seeing any scary
+update passing by.  journalctl, htop and dmesg do not show any obvious
+suspects.  Some things I considered:
+
+- Disabling some services e.g. tor or speech-dispatcher ⇒ no effect.
+- Uninstalling xserver-xorg-video-intel ⇒ no effect.
+- Upgrading systemd from backports ⇒ no effect.
+- htop sometimes shows pulseaudio acting up despite no application
+  playing or recording sound?
+- Maybe I should try reinstalling Debian's stable kernel?
+  - Luckily 5.7 was not uninstalled when upgrading to 5.8; booting on
+    5.7 solves all of the "choppiness" issues listed above.
+
+Now to pinpoint what's wrong with 5.8…
+***** TODO fixing
 * Someday
 ** fix xfce4-terminal opening links with firefox-esr
 ** fix Thunar opening images with Firefox instead of Ristretto