Slackware 14.2 x64 latest xscreensaver with multi-monitor doesen't restart X properly

After upgrading to latest xscreensaver-5.42 for 14.2 x64 one of my multi-head screens doesn't recover properly from power save blanking. This happens regardless of the WM/DE used. It corrects by restarting "x" in a second parallel session, or by closing the first session and restarting. After blanking and typing in password, the primary screen is OK, but the second screen image will be shifted to the left by 150-200 rows, leaving a black vertical line. After upgradepkg to the older xscreensaver-5.35-x86_64-2 this bug goes away.
I'm wondering if anyone else has seen this problem?
Does upgradepkg of xscreensaver-5.42 require a special step?


This happens under config
Kernel 4.19.12 or 4.19.14
Nouveau driver
Monitors Left (primary) 1600x900, right (1440x900)
Slackware 14.2 x64 standard full install (no multilib or WINE) only thing extra is AlienBob's qt5, qtwebkit, and Lumina desktop, all installed before xscreensaver upgrade and all working correctly with xscreensaver-5.35.
Session management by XDM
WM/DE's tested KDE, XFCE, FVWM, WindowMaker, Lumina

Let me know what other information to provide for troubleshooting this.

Slackware-14.2 was released in Mid 2016. This is 2019. In the intervening years, many libraries have been bumped up a version or two. For instance, slackware-14.2 came with mesa-11.x, IIRC. I have ~Current of December 2018 and it's mesa-18.3.

Did you get ALL your updates from a 14.2 repository, or were you downloading from current at various times?

Updates are from the slackware official repository and from AlienBob's repository. All patches, except now for this xscreensaver, have been applied in the past. The only unique files have been listed above. I'm not sure it happens with 4.4.157 PV's last kernel update. But I didn't want to load back to that kernel because of it's age. I recognize this might be a kernel issue, and I could re-install, reboot and test it that way. Will do that in the next 48 hours and report back here. But would like to know what log or debugging should be set to determine if this is xscreensaver or a kernel issue?

I would be more interested in seeing you downgrade xscreensaver than fart about with the kernel. Kernels load modules & drivers,and are not really involved in X afaik. I'd be surprised if that's the only place a kernel fault would show. Hardware, networking, modules, need an appropriate kernel, but hardly xscreensaver.

Originally Posted by business_kid Kernels load modules & drivers,and are not really involved in X afaik.

NVidia support and so do have both a kernel driver/module (nvidia.ko) as well as an Xorg one (nvidia_drv.so) but I would be amazed if that has anything to do with the xscreensaver as that's just an X client, with no interface with the kernel at all.
The kernel driver and so are only for the X server.

Originally Posted by bamunds After blanking and typing in password, the primary screen is OK, but the second screen image will be shifted to the left by 150-200 rows, leaving a black vertical line. After upgradepkg to the older xscreensaver-5.35-x86_64-2 this bug goes away. Monitors Left (primary) 1600x900, right (1440x900)

The only thing I can think of is that the some of the changes incorporated into the new release are trying to adjust to the disparity of your monitors' resolutions. I'm guessing that the amount of shift (1600-1440 = 160) is proportional to the difference in the horizontal part of the resolutions, as the vertical is the same.

My suggested solution is either to upgrade your right monitor to one with the same resolution as your primary, or (much cheaper!) is to just stick with the previous version, which didn't have this problem.

You might also get out with an xorg.conf.d/nn-video.conf. I set up an xorg.conf.d/20-video.conf in 2015. On the left, I had 1600x900; On the right, I had

• 1920xs1080 on hdmi OR
• 1280x720 on hdmi OR
• An unknown size on the stupid little 15 pin plug

You simply set up the details you need. You need a ServerLayout section: Each different piece of hardware needs 3 sections:

• Monitor (options like PreferredMode, Position, Primary go here)
• Device
• Screen (Options can be used here, including Position & Virtual setting)

Place the 1440x900 Monitor at 1601 0, and make the Virtual 3040x900. That should do it. Man xorg.conf is your friend.