[PATCH 4/6] compositor-drm/shell: Allow restore_output_mode() to work properly.

[Mario Kleiner]

Initialize output->native_mode with the initially chosen
mode for an output, so restore_output_mode() has something
to work with and can switch back from temporary selected modes
to the outputs native mode. Before, this was a no-op.

This allows an output to switch back to its default mode if
a former toplevel fullscreen shell surface created via method
WL_SHELL_SURFACE_FULLSCREEN_METHOD_DRIVER gets destroyed, or
demoted to non-fullscreen, or if modesetting on the output
failed.

Also fix desktop-shell's activate method to only restore
output mode on the output on which a shell surface gets
activated. This way fullscreen windows can mode switch their
output, but window switching and exposay still works in the
expected way.

Signed-off-by: Mario Kleiner <mario.kleiner.de at gmail.com>
---
 desktop-shell/shell.c | 3 ++-
 src/compositor-drm.c  | 4 ++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/desktop-shell/shell.c b/desktop-shell/shell.c
index 7d0e403..68846ed 100644
--- a/desktop-shell/shell.c
+++ b/desktop-shell/shell.c
@@ -2962,6 +2962,7 @@ shell_configure_fullscreen(struct shell_surface *shsurf)
 							 output->y - surf_y);
 				break;
 			} else {
+				weston_log("shell: Can't switch to temporary mode.\n");
 				restore_output_mode(output);
 				center_on_output(shsurf->view, output);
 			}
@@ -5089,7 +5090,7 @@ activate(struct desktop_shell *shell, struct weston_surface *es,
 	if (shsurf->state.fullscreen && configure)
 		shell_configure_fullscreen(shsurf);
 	else
-		restore_all_output_modes(shell->compositor);
+		restore_output_mode(shsurf->output);
 
 	/* Update the surface’s layer. This brings it to the top of the stacking
 	 * order as appropriate. */
diff --git a/src/compositor-drm.c b/src/compositor-drm.c
index 4a7baa1..9ddb6d6 100644
--- a/src/compositor-drm.c
+++ b/src/compositor-drm.c
@@ -2209,6 +2209,10 @@ create_output_for_connector(struct drm_compositor *ec,
 				    connector->count_modes == 0 ?
 				    ", built-in" : "");
 
+	/* Initialize output->native_mode field, so restore_output_mode() works. */
+	weston_output_mode_set_native(&output->base, output->base.current_mode,
+								  output->base.current_scale);
+
 	return 0;
 
 err_output:
-- 
1.9.1