one can switch from X to a virtual console. X restores the original video mode then "disconnects" (maybe just ceases accessing) the video device controls and buffers. this might also include telling/responding to the kernel so it (re)establishes whatever it intended to have there (often a text mode virtual console or a different instance of X). when X switches away to let something else access the display, what terminology is used to refer to the mode that X is in? is it "disconnected"? if you have 3 instances of X running, then you must have at least 2 (maybe all 3 when switched to a text console) instances in this mode, right?
ages ago, when computers were too slow for my needs in X, i would run many text mode virtual consoles (60 of them by doing some keyboard remapping) and few instances of X (3 of them in different hardware display modes). very often applications running on an instance of X would update the display. when i switched back, i would see the change. if there were many changes, i would see only the last change as if the buffers were updated in-place many times.
now days computers are fast enough i no longer use virtual console text mode and use virtual terminal software xfce4-terminal on X. and i run quite many instances of X.
Code:
lt1a/forums/3 /home/forums 6> w|cut -c10-
up 1 day, 3:03, 10 users, load average: 0.19, 0.42, 0.44
TTY FROM LOGIN@ IDLE JCPU PCPU WHAT
tty7 :0 Mon18 27:03m 1:34 0.18s xfce4-session
tty8 :1 Mon18 27:03m 4:03 0.20s xfce4-session
tty9 :2 Mon18 27:03m 2:36 0.20s xfce4-session
tty10 :3 Mon18 27:03m 1:32 0.17s xfce4-session
tty11 :4 Mon18 27:03m 15:40 0.22s xfce4-session
tty12 :5 Mon18 27:03m 1:46 0.18s xfce4-session
tty13 :6 Mon18 27:03m 1:39 0.17s xfce4-session
tty14 :7 Mon18 27:03m 1:39 0.17s xfce4-session
tty15 :8 Mon18 27:03m 1:27 0.18s xfce4-session
tty16 :9 Mon18 27:03m 5:37 9.48s xfce4-session
lt1a/forums/3 /home/forums 7>in the above command line, i used cut to slice off user names for privacy reasons. i have no idea what "Mon18" means. Monday at hour 18?
i can be switched away by two different means. one way is by workspaces. this is manged by the window manger within one instance of X. when i have N instances of X running, to do this on each, there will be N instances of the window manger running. i like near full-screen terminals and run one terminal per workspace with up to 9 running terminals (out of 10 or 20 workspaces)
the other way to switch is to "disconnect" from the active instance of X and "connect" to another. the display manager lightdm helps me do this. i have various keys bound to execute (directly, not by typing to a shell) the command to tell lightdm which instance of X i want to switch to. sometimes i have as many as 18 to 24 instances of X (each in a userid) running.
if lots of text output updates a terminal that i am not "connected" to, these changes update the buffers so that when i do "connect" to it, i see the last text that was updated in each place in the terminal window. if lots output happens on firefox (the browser i usually run) all these updates do not happen. firefox "hangs" at the first update it tries to do while its X instance is in "disconnected" mode.
anyone know what is happening? is Firefox doing something different with X.
i would like to have the buffers update continuously. one problem i am having is that when i play a video from YouTube to hear the music (a live radio station) it "hangs" as soon as as i switch to the instance of X that has what i am working on. usually i am working on several things and switch around often (like 5 or 6 times an hour) so having the music in one dedicated instance (user "music" at Ctrl+Shift+M).
this happened in Xubuntu 18.04.X and is happening with 20.04.X. i am on 20.04.6 having upgraded everything 2023-09-02.