Force software rendering by default

For: QubesOS/qubes-issues#9268
For: QubesOS/qubes-gui-agent-linux#214

rpm_spec/core-dom0-linux.spec.in

@@ -153,6 +153,7 @@ install -m 644 system-config/12-qubes-ignore-lvm-devices.rules $RPM_BUILD_ROOT%_
 install -m 644 system-config/11-qubes-ignore-zvol-devices.rules $RPM_BUILD_ROOT%_udevrulesdir
 install -m 644 system-config/99z-qubes-mark-ready.rules $RPM_BUILD_ROOT%_udevrulesdir
 install -m 644 -D system-config/disable-lesspipe.sh $RPM_BUILD_ROOT/etc/profile.d/zz-disable-lesspipe.sh
+install -m 644 -D system-config/disable-gpu-accel.sh $RPM_BUILD_ROOT/etc/profile.d/zz-disable-gpu-accel.sh
 install -m 755 -D system-config/kernel-grub2.install $RPM_BUILD_ROOT/usr/lib/kernel/install.d/80-grub2.install
 install -m 755 -D system-config/kernel-xen-efi.install $RPM_BUILD_ROOT/usr/lib/kernel/install.d/90-xen-efi.install
 install -m 755 -D system-config/kernel-remove-bls.install $RPM_BUILD_ROOT/usr/lib/kernel/install.d/99-remove-bls.install
@@ -315,6 +316,7 @@ chmod -x /etc/grub.d/10_linux
 %attr(0644,root,root) /etc/cron.d/qubes-sync-clock.cron
 /etc/cron.daily/lvm-cleanup
 %config(noreplace) /etc/profile.d/zz-disable-lesspipe.sh
+%config(noreplace) /etc/profile.d/zz-disable-gpu-accel.sh
 %config(noreplace) /etc/dnf/protected.d/qubes-core-dom0.conf
 %_presetdir/75-qubes-dom0.preset
 %_presetdir/99-qubes-default-disable.preset

system-config/disable-gpu-accel.sh

@@ -0,0 +1,4 @@
+if ! test -f /var/run/qubes-service/gpu-accel; then
+  export GSK_RENDERER="cairo" GDK_DEBUG="gl-disable vulkan-disable" \
+         LIBGL_ALWAYS_SOFTWARE=1
+fi