Issue

Emacs redraws sometimes partially while scrolling in X.org on VMWare or VirtualBox. I tested only on Windows host OS.

Following error messages are output in /var/log/Xorg.0.log when this problem occurs.

[  1278.046] (EE) vmwgfx_scanout_update: failed to send dirty (-22, Invalid argument)

There are many reports of this problem:

I confirmed it happens even in one CPU configuration.

Vim seems to have the similar problems:

Workarounds

There are several workarounds I tried.

Use Cairo

Emacs 25 supports Cairo by configure --with-cario. This workaround does not hide the problem completely. This makes it less frequently.

Synchronous mode

  emacs -xrm "emacs.synchronous: true"

This makes Emacs somewhat slow.

Call redraw-display after scroll

(when (eq window-system 'x)
  (add-hook 'window-scroll-functions (lambda (&rest x) (run-with-idle-timer 0.5 nil 'redraw-display))))

Use compiz

Using compiz solves the problem. Unfortunately, compiz makes painting slow.

Use Xephyr

Xephyr also solve the problem. On the other hand, Xnest doesn’t help.

Use X.Org fbdev driver

/etc/X11/xorg.conf:

Section "Device"
	Identifier "card 0"
	Driver "fbdev"
EndSection

Switch wallpaper images every seconds

This triggers repainting whole scrren every seconds.

Switch to other window and back to Emacs

Press Alt-Tab and Alt-Tab to switch window to repaint.

Investigation

libX11 API calls can be observed by ltrace:

ltrace -l libX11\* emacs

The following API are called frequently during scroll.

emacs->XDrawImageString(0x306e800, 0x28000b0, 0x3b47ee0, 264) = 0
emacs->XSetClipMask(0x306e800, 0x3b47ee0, 0, 0)             = 1
emacs->XSetClipRectangles(0x306e800, 0x3b47ee0, 0, 0)       = 1
emacs->XDrawImageString(0x306e800, 0x28000b0, 0x3b47ee0, 296) = 0
emacs->XSetClipMask(0x306e800, 0x3b47ee0, 0, 0)             = 1
emacs->XSetClipRectangles(0x306e800, 0x3b47ee0, 0, 0)       = 1

I created a test program and filed a bug report.

Apply a patch and compile the driver

I attached my patch.

This is the install steps for Fedora.

dnf download --source xorg-x11-drv-vmware
sudo dnf builddep xorg-x11-drv-vmware
aunpack xorg-x11-drv-vmware-13.0.2-11.20150211git8f0cf7c.fc24.src.rpm
aunpack xorg-x11-drv-vmware-13.0.2-11.20150211git8f0cf7c.fc24.src/xf86-video-vmware-20150211.tar.bz2
cd xf86-video-vmware-20150211
patch -p0 ~/tmp/vmwgfx-dirty-union.patch
autoreconf -isv
./configure --prefix=$HOME/opt
make 
make install

Create /etc/X11/xorg.conf with the following content.

Section "Files"
    ModulePath "/home/fujii/opt/lib/xorg/modules,/usr/lib64/xorg/modules"
EndSection

Log out and log in (lightdm restarts X server).

See the log /var/log/Xorg.0.log to check your driver is loaded.

This is for Ubuntu 17.4:

sudo apt-get install devscripts
sudo apt-get build-dep xserver-xorg-video-vmware
apt-get source xserver-xorg-video-vmware
cd xserver-xorg-video-vmware-13.2.1
patch -p0 < ../vmwgfx-dirty-union.patch
debuild -i -us -uc -b
cd ..
sudo dpkg -i xserver-xorg-video-vmware_13.2.1-1build1_amd64.deb