Fix segfault in wlr_output_manager_v1_set_configuration

Calling wlr_output_manager_v1_set_configuration with an enabled output
and a NULL mode is incorrect if the output doesn't support modes.

When DPMS'ing an output, wlr_output_enable(output, false) is called.
This de-allocates the CRTC and sets wlr_output.current_mode to NULL.

Because we mark DPMS'ed outputs as enabled, we also need to provide a
correct output mode. Add a field to sway_output to hold the current
mode.

Closes: https://github.com/swaywm/wlroots/issues/1867

1 files changed, 2 insertions, 0 deletions

diff --git a/include/sway/output.h b/include/sway/output.h
index c52b3094..7d7057e1 100644
--- a/include/sway/output.h
+++ b/include/sway/output.h
@@ -32,6 +32,8 @@ struct sway_output {
         int lx, ly; // layout coords
         int width, height; // transformed buffer size
         enum wl_output_subpixel detected_subpixel;
+        // last applied mode when the output is DPMS'ed
+        struct wlr_output_mode *current_mode;
 
         bool enabled, configured;
         list_t *workspaces;