I'd like to suggest the attached patch for inclusion into the xscreensaver ebuild. It allows one to specify a "screensBlankOnly" property in ones ~/.xscreensaver file, which specifies, on a multi-screen display, screens that should not have a screensaver hack started on them, but rather only be blanked. The rationale is that if one has a multiscreen display where, for example, one display on connected to your TV, it's unnecessary to waste CPU time on running a screensaver on the TV which probably isn't on anyway. Thus, this patch allows the TV to just be blanked instead of having a screensaver hack running on it. I've suggested it upstream to JWZ, but I have not received a reply at all.
Created attachment 40439 [details, diff] Hack restriction patch
Does this not happen in 4.16 or 4.20. I see this note in the README: Changes since 4.12: * On Xinerama systems, xscreensaver now runs one hack on each monitor (just like in "real" multi-head mode) instead of running one hack stretching across all the screens. Note that for this to work with any 3rd party screensavers, they must update their "vroot.h" file.
That's a completely different (and orthogonal) thing. What that means is that, previously (before 4.12), xscreensaver would run exactly one hack that was stretched over all screens of a display. In 4.12 and later, it will run one hack per screen. Also, that only affects xscreensaver if you use Xinerama. In other words, it makes Xinerama displays behave as non-Xinerama displays. What this patch does is it prevents hacks from being run on the screens that you specify, and instead only blanks them. Regardlessly of whether one uses Xinerama.
gentoo does not provide features for programs which upstream does not wish to include unless there is a security problem also, look for the "blank after" feature
