drm/virtio: fix unblank
When going through a disable/enable cycle without changing the
framebuffer the optimization added by commit
3954ff10e06e ("drm/virtio:
skip set_scanout if framebuffer didn't change") causes the screen stay
blank. Add a bool to force an update to fix that.
v2: use drm_atomic_crtc_needs_modeset() (Daniel).
Cc: 1882851@bugs.launchpad.net
Fixes:
3954ff10e06e ("drm/virtio: skip set_scanout if framebuffer didn't change")
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Tested-by: Jiri Slaby <jirislaby@kernel.org>
Tested-by: Diego Viola <diego.viola@gmail.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20200818072511.6745-2-kraxel@redhat.com