Hi misc@, I did not find any mentioning of OpenBSD Xenocara use of the "dummy" video driver on mailing list nor web. Digging into code and documentation, I think it looks like it's available and should work.
I'll try this out soon, this is mostly to mention the topic and to check if anyone has any comments. The idea is to run a dummy framebuffer X server which is resizeable, as backend for X11Vnc. Support for dynamic resizing of the X framebuffer, which is delivered through Xrandr by the VNC framebuffer resize feature, is great when you VNC in from computers with different resolutions. The conventional way to resize the X framebuffer would be to restart Xvfb(1) (http://man.openbsd.org/Xvfb.1) with the new resolution specified as command line argument. I got the idea of the existence of a dynamically resizeable virtual X backend from the X11vnc's manual page (https://linux.die.net/man/1/x11vnc) mentioning of the author's "Xdummy" script where "an advantage of Xdummy over Xvfb is that Xdummy supports RANDR dynamic screen resizing." The script's sourcecode is at http://www.karlrunge.com/x11vnc/Xdummy , X11vnc's manual goes on to say that it "only works on Linux", derp, and the script has shellscript and C parts that seem to implement privilege separation logics that OpenBSD already provides, and what it does overall seems to be to generate the xorg.conf(5) configuration attached below. The "Display drivers:" section in http://man.openbsd.org/xorg.conf.5#SEE_ALSO lists no dummy driver, however, a "xf86-video-dummy" driver is located in the source tree (https://cvsweb.openbsd.org/cgi-bin/cvsweb/xenocara/driver/). So I guess this should be tested and experimented with. Any comments are welcome. The X11vnc command line to deliver resizing should be "x11vnc -display :0 -localhost -xrandr resize". I presume that the xorg.conf below neither works nor is practical on OpenBSD, but probably a good one can be created easily with it as inspiration. Thanks, Tinker Section "ServerLayout" Identifier "Layout0" Screen 0 "Screen0" InputDevice "Keyboard0" "CoreKeyboard" InputDevice "Mouse0" "CorePointer" EndSection Section "Files" EndSection Section "Module" Load "dbe" Load "extmod" Load "freetype" Load "glx" EndSection Section "InputDevice" Identifier "Mouse0" Driver "mouse" Option "Protocol" "auto" Option "Device" "/dev/psaux" Option "Emulate3Buttons" "no" Option "ZAxisMapping" "4 5" EndSection Section "InputDevice" Identifier "Keyboard0" Driver "kbd" EndSection Section "Monitor" Identifier "Monitor0" VendorName "Unknown" ModelName "Unknown" HorizSync 30.0 - 130.0 VertRefresh 50.0 - 250.0 Option "DPMS" EndSection Section "Device" Identifier "Device0" Driver "dummy" VideoRam 24000 VendorName "foovideo Corporation" EndSection Section "Screen" Identifier "Screen0" Device "Device0" Monitor "Monitor0" DefaultDepth 24 SubSection "Display" Depth 24 Modes "1280x1024" EndSubSection EndSection Section "ServerFlags" Option "DontVTSwitch" "true" Option "AllowMouseOpenFail" "true" Option "PciForceNone" "true" EndSection
