Without OpenGL and without shared memory, QEMU does not send a Scanout
to a D-Bus display client when VGA text mode changes its size.  The
client gets only Updates for the rows of the new size, although
ui/dbus-display1.xml says that Update is only called after a Scanout
call.

Patch 1 sends a Scanout of the whole surface at the first update after
a surface switch.  With shared memory, dbus_scanout_map() already does
the same with ScanoutMap.  Patch 2 adds a test case for this to
dbus-display-test.

v1: https://lore.kernel.org/qemu-devel/20261022053535.38791-1-christian@quante.one/

Changes since v1:
- patch 1: clear the flag also when ScanoutMap is sent, and name
  ScanoutMap in the comment on the field (Marc-André Lureau)
- Marc-André Lureau's Reviewed-by carried over to both patches: patch 1
  changes only as he suggested, patch 2 is unchanged
- rebased on current master

Tests with v2, on master 4f4225874d:

 - dbus-display-test: with the series, all six test cases pass.  One of
   them, console/map, waits for a ScanoutMap, so it runs the new line in
   dbus_scanout_map().  With patch 2 alone, the new test case
   text-resize fails ("Update" == "Scanout").  With patch 1 alone, the
   five other test cases pass.

 - I did not run the Windows NT 4.0 test from v1 again.  v2 changes
   only the path with shared memory, and my D-Bus client does not
   implement org.qemu.Display1.Listener.Unix.Map, so for this client
   the code runs as in v1.

 - The Win32 variant of dbus_scanout_map() gets the same line.  I have
   no Windows build here, so it is not compiled.

checkpatch.pl is clean.

Christian Quante (2):
  ui/dbus: send a Scanout before the first Update of a new surface
  tests/qtest/dbus-display-test: check the Scanout after a text resize

 tests/qtest/dbus-display-test.c | 162 +++++++++++++++++++++++++++++---
 ui/dbus-listener.c              |  10 +-
 2 files changed, 157 insertions(+), 15 deletions(-)


base-commit: 4f4225874d4d3747ec1142e935dbd314218992fa
-- 
2.53.0