Incompatibility with xcompmgr -f

google / xsecurelock

X11 screen lock utility with security in mind

Apache License 2.0

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Incompatibility with xcompmgr -f #24

Closed divVerent closed 6 years ago

divVerent commented 6 years ago

xsecurelock is currently not compatible with xcompmgr -f; with this combination, the screen is not blanked while locked because both xcompmgr and xsecurelock are drawing to the same destination.

Currently no fix is known; possible workarounds seem to be:

compton -f (but without -i option, apparently)
compton -f --backend glx --paint-on-overlay (allows -i option)
passing XSECURELOCK_NO_COMPOSITE=1 to xsecurelock (which may make transparent notifications show up on top of the lockscreen)

divVerent commented 6 years ago

We may want to use https://stackoverflow.com/questions/33195570/detect-if-compositor-is-running to implement a compositor blacklist mechanism.

divVerent commented 6 years ago

What's interesting is that xcompmgr does not actually request the Composite Overlay Window. It manages to draw on top of XSecureLock without using that.

This leaves only two possibilities:

It manages to redirect XSecureLock's subwindows of the COW, or
The XRender extension, even though targeted at the root window, actually draws above the COW.

divVerent commented 6 years ago

Issue reproduces with both nvidia and nouveau, so it's probably not a graphics driver bug.

Next step will be trying to find out if xcompmgr can see XSecureLock's window, and if we can prevent it from seeing it.

divVerent commented 6 years ago

After adding some debugging prints to xcompmgr's code: out of all possible windows it could be redirecting, xcompmgr redirects the composite overlay window itself.

Probably not much that can be done there, then. Simply incompatible.

tycho-kirchner commented 5 months ago

Hi and sorry for necrobumping. I wanted to use xsecurelock with my fork of xcompmgr/compton and realized that indeed it does not work.

Probably not much that can be done there, then. Simply incompatible

If that was true, why does it work in gnome-/mate-screensaver? Additionally, these screensavers do not draw notifications on the lockscreen, while this happens indeed as described in xsecurelock's README. Possibly realted: https://github.com/google/xsecurelock/issues/97