[?]Strange persistent artifact on screen with Knoppix 8.6 after "Suspend-Restart"s

[rajibando]

Yes, friends, I know that I would immediately be advised to upgrade to the latest knoppix. But currently I have some additional packages installed as a persistent set up which would need time to be ported.

So please forgive me for my not being able to follow up on that advice presently.

Regarding the problem:
---------------------------------
For a long time, with 8.6.0, I have noticed that after a couple of system "Suspend"s and restarts an artifact appears, and remains persistently on the screen which is bothersome. It even appears on Screenshots. It is clearly because of a program, but I can't identify which.

When the system is restarted the artifact goes away, only to reappear after the same couple of Suspends-Restarts.

The relevant portions from hardinfo is:
-Display-
Resolution : 1366x768 pixels
Vendor : The X.Org Foundation
Version : 1.20.4
[...]
Monitor 0 : 1366x768 pixels
-OpenGL-
Vendor : Intel Open Source Technology Center
Renderer : Mesa DRI Intel(R) HD Graphics 520 (Skylake GT2) x86/MMX/SSE2
Version : 3.0 Mesa 19.2.1
Direct Rendering : Yes
[...]
-GPU Drawing-
Intel(R) Core(TM) i3-6006U CPU @ 2.00GHz 4x 2000.00 MHz 3481.93

A screenshot of the artifact is uploaded at my drive (since the image couldn't be uploaded/attached here) : https://drive.google.com/file/d/1ZtO...x-pKlSIR0RH-C/
Could I please be helped in removing this artifact from my screen over multiple "Suspend-Restart"s?

[szzsqing1]

Although you do not write about this, I think that this problem does not occur in live mode, and, as you said, it is related to your persistent changes. Probably it is a Knoppix LXDE (X, Compiz?) bug. I remember that I had similar experiences, not after suspend, but in plain LXDE session: did not disappear the window size notification from the desktop. If I remember well, I resolved this by resizing again a window with mouse or logging out/in from X. But the latest is also problematic (at least in Knoppix 9.1 which I use), the implementation of logging out/in is buggy. If not a problem for you, you can use Gnome or KDE, or replace your persistent /home/knoppix directory with the live version one, of course in a live session (first save your important configuration dirs, files, and after replace them back). Maybe it helps if you use LXDE-Openbox session instead of LXDE-Compiz. Unfortunately in current Knoppix you have to use the buggy Compiz, cannot switch to LXDE-Openbox.

Nowadays the Knoppix LXDE implementation is pretty buggy, a lot of things changed during Knoppix history... There are Knoppix scripts that are not needed anymore or does not function as expected. Should be done a general maintenance. Or even better changing the default LXDE to LXQt, wich is actively maintained, or to Trinity desktop, wich has a lot of features, it is lightweight, and actively maintained, too.

[rajibando]

Thank you, szzsqing1, for your informative post.Your sharing of your own experience really helped.

... I think that this problem does not occur in live mode, and, as you said, it is related to your persistent changes ....

I haven't checked, as I use persistent always. I will, in the coming days, and post my report.

... I remember that I had similar experiences, not after suspend, but in plain LXDE session: did not disappear the window size notification from the desktop...

In my case, the artifact appears after revival from Suspend.

... If I remember well, I resolved this by resizing again a window with mouse ...

I tried this, but can't seem to identify the window that is the mischief-maker.

... or logging out/in from X. .

Yes, this too works.

... But the latest is also problematic (at least in Knoppix 9.1 which I use), the implementation of logging out/in is buggy. If not a problem for you, you can use Gnome or KDE, or replace your persistent /home/knoppix directory with the live version one, of course in a live session (first save your important configuration dirs, files, and after replace them back)..

Thank goodness that I didn't upgrade to 9.1! But one note: I use an entire ext4 partition with persistent. I have an old post describing the steps. With a file knoppix-data.inf at the root of the partition, with the line having these entries:

(partitionNumber)      /(where the data files are stored)    (partition type)

... Maybe it helps if you use LXDE-Openbox session instead of LXDE-Compiz. Unfortunately in current Knoppix you have to use the buggy Compiz, cannot switch to LXDE-Openbox..

Ok. I will try. Actually, I haven't ever used openbox seriously, so I am not very comfortable with it. Will try. Knoppix has these options: kde|gnome|icewm|fluxbox|openbox|larswm|evilwm|twm.
I will also try with no3D.

... Or even better changing the default LXDE to LXQt, wich is activey maintained, or to Trinity desktop, wich has a lot of features, it is lightweight, and actively maintained, too.

I am not sure if Trinity or LXQt is at all in the Knoppix 8.6 DVD ISO. I will check.

Actually, I have a Debian environment installed, but I prefer using Knoppix, as I have been using it consistently for the last 14 years, from 5.something. I have wonderful memories with Knoppix and a few good friends, whom I don't find here any more.

In the end, thanks once more for replying to my post, sharing your experience. Much appreciated.

[szzsqing1]

I tried this, but can't seem to identify the window that is the mischief-maker.

Yes, it happened in the past and somehow the "bug" was saved, and now you cannot find that specific reason. If it was saved in some cache maybe deleting the (hidden) cache dirs in your home dir also helps. But I really do not know the reason and as the LXDE dev has stopped there are not too much info on the net.

When I mentioned LXQt and TDE, I suggested this to the developer of Knoppix OS, to replace the present default LXDE, as a better option. I did not mean that now it is actually an option in KNX to choose. Of course you can try to install these desktop environments, but not much chance to succeed. I already tried to install TDE and it is just impossible in Knoppix (because this a special Debian distro, FrankenDebian)...

Also from kde|gnome|icewm|fluxbox|openbox|larswm|evilwm|twm options actually only the first two are real options. In past maybe the others were real options but nowadays they are dropped. Openbox boot option still worked not too long ago, but not in the current version. If you start (-ed in the past) KNX with OB you get a very simple OB environment without lxsession, lxpanel, lxmenu, etc. So not very usable. What I recommended you, LXDE-OB is a real LX session with OB window manager, not with Compiz window manager (the main difference is that you will not get Compiz effects, but everything else can be configured and works very well). This could be accomplished in older KNX versions (by editing some config files). Otherwise, LXDE-OB is the most used LX session type, Debian Live LXDE uses this, too.

LXDE-OB can be used also in current KNX instead of LXDE-Compiz, but needs to be installed some debs. Some time ago I read a tutorial about this issue, and this evening I tried to find that article. Without success because meantime that page disappeared from the net!

http://students.engr.scu.edu/~sschaeck/

Fortunately there is a website (archive.org) which archives the WWW (among other things), and I have found the page there. Here is the URL (saved at 2019-11-14):

How to get most out of Knoppix 8
https://web.archive.org/web/20191114210258/http://students.engr.scu.edu/~sschaeck/knoppix/index.html

So, it seems that also in your version you have to install some debs in order to use LXDE-Openbox. But according to the tutorial it is possible. I did not try. Good luck you!

[rajibando]

... LXDE-OB can be used also in current KNX instead of LXDE-Compiz, but needs to be installed some debs. ...

Since I use the earlier version, I shall try once. Thank you for your links and suggestions. Also, in the meanwhile I shall try identifying the mischief-making program drawing that window and making that artifact appear.

[rajibando]

I solved the nagging issue on LXDE. It seems that after power ON from suspend, if the program drawing the window is identified, and the window frame is resized, the artefact vanishes. In many of the cases, pcmanfm creates the artefacts. The issue of artefact took much time to be solved. Perhaps my brain is showing me a sign of its ageing.

I offer my apologies for the typo, writing Artefact as Artifact. Overlooked it completely until now, even with spellchecker ON. Another sign!