Introduce test_output_config

This function checks whether the backend would accept an output
configuration, without applying the changes.

2 files changed, 58 insertions, 28 deletions

diff --git a/include/sway/config.h b/include/sway/config.h
index 94ce6214..b541ff0d 100644
--- a/include/sway/config.h
+++ b/include/sway/config.h
@@ -691,6 +691,8 @@ void merge_output_config(struct output_config *dst, struct output_config *src);
 
 bool apply_output_config(struct output_config *oc, struct sway_output *output);
 
+bool test_output_config(struct output_config *oc, struct sway_output *output);
+
 struct output_config *store_output_config(struct output_config *oc);
 
 struct output_config *find_output_config(struct sway_output *output);
diff --git a/sway/config/output.c b/sway/config/output.c
index cbcf713b..1a37c47c 100644
--- a/sway/config/output.c
+++ b/sway/config/output.c
@@ -331,34 +331,27 @@ static int compute_default_scale(struct wlr_output *output) {
         return 2;
 }
 
-bool apply_output_config(struct output_config *oc, struct sway_output *output) {
+static void queue_output_config(struct output_config *oc,
+                struct sway_output *output) {
         if (output == root->noop_output) {
-                return false;
+                return;
         }
 
         struct wlr_output *wlr_output = output->wlr_output;
 
-        if (oc && !oc->enabled) {
-                // Output is configured to be disabled
-                sway_log(SWAY_DEBUG, "Disabling output %s", oc->name);
-                if (output->enabled) {
-                        output_disable(output);
-                        wlr_output_layout_remove(root->output_layout, wlr_output);
-                }
+        if (oc && (!oc->enabled || oc->dpms_state == DPMS_OFF)) {
+                sway_log(SWAY_DEBUG, "Turning off output %s", wlr_output->name);
                 wlr_output_enable(wlr_output, false);
-                return wlr_output_commit(wlr_output);
+                return;
         }
 
-        bool was_enabled = output->enabled;
-        output->enabled = true;
-
-        if (!oc || oc->dpms_state != DPMS_OFF) {
+        if (!oc) {
                 sway_log(SWAY_DEBUG, "Turning on output %s", wlr_output->name);
                 wlr_output_enable(wlr_output, true);
 
                 if (oc && oc->width > 0 && oc->height > 0) {
-                        sway_log(SWAY_DEBUG, "Set %s mode to %dx%d (%f Hz)", oc->name, oc->width,
-                                oc->height, oc->refresh_rate);
+                        sway_log(SWAY_DEBUG, "Set %s mode to %dx%d (%f Hz)",
+                                wlr_output->name, oc->width, oc->height, oc->refresh_rate);
                         set_mode(wlr_output, oc->width, oc->height,
                                 oc->refresh_rate, oc->custom_mode == 1);
                 } else if (!wl_list_empty(&wlr_output->modes)) {
@@ -372,7 +365,6 @@ bool apply_output_config(struct output_config *oc, struct sway_output *output) {
                 sway_log(SWAY_DEBUG, "Set %s subpixel to %s", oc->name,
                         sway_wl_output_subpixel_to_string(oc->subpixel));
                 wlr_output_set_subpixel(wlr_output, oc->subpixel);
-                output_damage_whole(output);
         }
 
         if (oc && oc->transform >= 0) {
@@ -395,19 +387,51 @@ bool apply_output_config(struct output_config *oc, struct sway_output *output) {
         }
 
         if (oc && oc->adaptive_sync != -1) {
+                sway_log(SWAY_DEBUG, "Set %s adaptive sync to %d", wlr_output->name,
+                        oc->adaptive_sync);
                 wlr_output_enable_adaptive_sync(wlr_output, oc->adaptive_sync == 1);
         }
+}
+
+bool apply_output_config(struct output_config *oc, struct sway_output *output) {
+        if (output == root->noop_output) {
+                return false;
+        }
+
+        struct wlr_output *wlr_output = output->wlr_output;
+
+        bool was_enabled = output->enabled;
+        if (oc && !oc->enabled) {
+                // Output is configured to be disabled
+                sway_log(SWAY_DEBUG, "Disabling output %s", oc->name);
+                if (output->enabled) {
+                        output_disable(output);
+                        wlr_output_layout_remove(root->output_layout, wlr_output);
+                }
+        } else {
+                output->enabled = true;
+        }
+
+        queue_output_config(oc, output);
+
+        if (!oc || oc->dpms_state != DPMS_OFF) {
+                output->current_mode = wlr_output->pending.mode;
+        }
 
         sway_log(SWAY_DEBUG, "Committing output %s", wlr_output->name);
         if (!wlr_output_commit(wlr_output)) {
-                // Failed to modeset, maybe the output is missing a CRTC. Leave the
-                // output disabled for now and try again when the output gets the mode
-                // we asked for.
-                sway_log(SWAY_ERROR, "Failed to modeset output %s", wlr_output->name);
+                // Failed to commit output changes, maybe the output is missing a CRTC.
+                // Leave the output disabled for now and try again when the output gets
+                // the mode we asked for.
+                sway_log(SWAY_ERROR, "Failed to commit output %s", wlr_output->name);
                 output->enabled = was_enabled;
                 return false;
         }
 
+        if (config->reloading) {
+                output_damage_whole(output);
+        }
+
         if (oc) {
                 enum scale_filter_mode scale_filter_old = output->scale_filter;
                 switch (oc->scale_filter) {
@@ -424,7 +448,6 @@ bool apply_output_config(struct output_config *oc, struct sway_output *output) {
                 if (scale_filter_old != output->scale_filter) {
                         sway_log(SWAY_DEBUG, "Set %s scale_filter to %s", oc->name,
                                 sway_output_scale_filter_to_string(output->scale_filter));
-                        output_damage_whole(output);
                 }
         }
 
@@ -448,12 +471,6 @@ bool apply_output_config(struct output_config *oc, struct sway_output *output) {
                 output_configure(output);
         }
 
-        if (oc && oc->dpms_state == DPMS_OFF) {
-                sway_log(SWAY_DEBUG, "Turning off output %s", oc->name);
-                wlr_output_enable(wlr_output, false);
-                wlr_output_commit(wlr_output);
-        }
-
         if (oc && oc->max_render_time >= 0) {
                 sway_log(SWAY_DEBUG, "Set %s max render time to %d",
                         oc->name, oc->max_render_time);
@@ -463,6 +480,17 @@ bool apply_output_config(struct output_config *oc, struct sway_output *output) {
         return true;
 }
 
+bool test_output_config(struct output_config *oc, struct sway_output *output) {
+        if (output == root->noop_output) {
+                return false;
+        }
+
+        queue_output_config(oc, output);
+        bool ok = wlr_output_test(output->wlr_output);
+        wlr_output_rollback(output->wlr_output);
+        return ok;
+}
+
 static void default_output_config(struct output_config *oc,
                 struct wlr_output *wlr_output) {
         oc->enabled = 1;