blank screen on startx for kde at kernel 5.10.4
 

I just installed kernel 5.10.4 packages from slackware64 -current and now startx gives a blank screen after a few moments.

I boot to runlevel 3, login as my regular user, and issue "exec startx" or just "startx". Plasma starts to initialize with the icon in the middle of the screen and "Plasma made by kde" in the lower right corner, then goes black.

CTRL+ALT+BACKTAB doesn't kill it. I have to boot my system to recover.

I don't normally startx when I login as root, but I tried it to see what would happen. Plasma/kde initialized fine. I was able to logout my session using the menu option and I could terminate kde via CTRL+ALT+BACKTAB and get back to the command line.

Either way I end the session, the screen goes black for about 8 seconds before kde finally exits and lands me back on the command line. Back at the command line I see Xorg error messages like these:

So maybe permissions issue, or an X config difference between root and my normal user?

I'm using the onboard graphics and kernel driver is i915.

Output from "lspci -k | grep -iA3 vga"

What happens if root runs SDDM from runlevel 3?

sddm from root appears to work, but it starts a Wayland session that I can't login from.

In the lower left corner of the screen, it says "Desktop Session: Plasma (Wayland)" There are login choices for my three normal user accounts, but not for root. When I enter my password, the login screen blanks for a second then re-displays. It doesn't log me in. If I enter an invalid password, it says "Login failed" and leaves me at the login screen.

There is a dropdown arrow next to the "Plasma (Wayland)" with choices for "Plasma (Wayland)", "Plasma", "Xfce Session", and "Plasma (Failsafe)".

When I try "Xfce Session", it works. I don't use Xfce, so I don't know what it's supposed to look like, but it appears to be a functional desktop, blue background with a mouse picture. I can start Firefox and various utilities, and it all seems to work.

None of the other options work. I see the Plasma icon in the center of the screen for a moment or so when trying "Plasma" or "Plasma (Failsafe)", then the session terminates and I get some error messages like below, and I have to CTRL+C to get back to the command line.

When I try sddm from my unprivileged user account, I don't get a login screen. Just messages like the following:

and

I never installed ktown or vtown. I just waited for KDE 5 to hit -current and installed using slackpkg. It was working before I upgraded to kernel 5.10.4 from 5.4.71.

Another odd thing. While sitting at the command line, the screen eventually blanks, and once it does, I can't get back to the command line again. Normally hitting a key on the keyboard would restore the display, but now it just stays blank and I have to boot my system to recover.

I booted and logged on again as unprivileged user, then tried xwmconfig from command line, and selected kde, which is what it already was, then entered startx again ... and it worked. Plasma started. Hopefully not a fluke. xwmconfig must have fixed something somewhere.

Now I need to wait and see what happens when my monitor goes to sleep again.

My system is still not coming back from what I assume is the monitor power-saving mode. The only thing I can do once the monitor blanks is to boot the system. I've booted more times today that I did in the past three years. The system is still running when it goes blankety-blank. I can ssh to it. I don't see any obvious errors in /var/log/messages or dmesgs, except for maybe this that I don't recall ever seeing before:

The good thing is that startx works again. If anyone else has a problem with startx to kde desktop, maybe try running xwmconfig and selecting your preferred desktop again. That apparently fixed my plasma startup problem.

Meanwhile, I may have to go back to a previous kernel because of the blankety-blank problem. Can I use slackpkg to do that? How to do that if I want to go back to 5.4.71, which was working fine before I went to 5.10.4?

Hi Z038,

I see you wrote you are using an Intel video 'card' and the i915 driver. A great many people have a large amount of trouble with that hardware and that driver --- for years. My experience with various aspects of the trouble began in 2016...

It appears you use the console more than a little bit. One of the things I did early on was to disable console screen blanking, because of the i915 problem. I added this stanza to /etc/rc.d/rc.local
You might want to experiment with
Or some combination of the three (blank, powersave, and powerdown).

Thank you baumei. I issued the setterm command from my non-privileged user command line just now, and I'm waiting to see if it is effective. If so, I'll put it in my rc.local like you did. The screen blanking has always annoyed me anyway. I didn't know you could disable it.

That's interesting to know about the Intel video and graphics. It worked when I built this system, so I figured I'd avoid the expense of buying an add-on graphics card since I have no need for anything more graphically challenging than a browser display. Mostly just command line emacs and git does the trick for me.

I'll buy a cheap video card if it makes my life easier. But not Nvidia. From what I've read, that brand is problematic too.

Hi Z038,

According to my recollection I have always run setterm as root. I have no idea what setterm would do for an ordinary user. Please let me know what you find out. :-)

You could try a different driver as well. The vesa driver used to work for me when the generic intel driver failed. it might be enough to get you up and running while you try and work around the problem. Set it in your xorg.conf and more than likely it will work, but dont expect any 3d acceleration etc and mplayer generally isnt happy doing complex playbacks on the vesa driver, like x265, etc.

In -current, there is /etc/rc.d/rc.setterm

Thanks to baumei and Petri Kaukasoina for the setterm suggestions and info. It's effective in keeping the terminal from blanking if you are at the command line. It doesn't affect behavior in KDE. If KDE blanks the screen, I have to boot the system, as there is no coming back from a blank screen.

In KDE System Settings, I've disabled the Screen Energy Saving option in the Energy Savings tab of the Power Management settings. Hopefully that will keep KDE from blanking the screen. Meanwhile, I just tried to change my display resolution, and that caused the screen to be blanked, and the screen is now gone for good. I'm rebooting now.

What a pain this is.

Firstly you should see a menuitem to choose whichever WM/DE you prefer when the SDDM Login/CHOOSER screen loads. There you can click the down arrow and select X11 Plasma, Xfce or whatever else you have installed and configured.

I, too, have problems with auto jump to VT7. The only solutions I know are to manually invoke "Alt-F7" or edit /etc/sddm.conf to "MinimumVT=1"

Learning Curves are quite often painful but usually worth the effort and pain. Struggle makes us stronger but as the old cliche goes, "Everybody wants to go to Heaven but nobody wants to die" ;)