From cd8464218b2ca82323fd3312270c2dfafc8716ea Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Michel=20D=C3=A4nzer?= <mdaenzer@redhat.com>
Date: Mon, 28 Feb 2022 18:08:23 +0100
Subject: [PATCH] xwayland: Add RandR mode for the native resolution if it fits
 in logical

Always add it as the first mode, which makes it considered the preferred
mode per the RandR protocol.

Mark the logical mode as currently set.

v2:
* Drop change in xwl_window_should_enable_viewport which seems
  unnecessary and coult result in a crash. (Olivier Fourdan)
* Use 'native' instead of 'actual'.
---
 hw/xwayland/xwayland-output.c | 41 +++++++++++++++++++++++++++++------
 1 file changed, 34 insertions(+), 7 deletions(-)

diff --git a/hw/xwayland/xwayland-output.c b/hw/xwayland/xwayland-output.c
index 338c98f29..85c2b7059 100644
--- a/hw/xwayland/xwayland-output.c
+++ b/hw/xwayland/xwayland-output.c
@@ -378,27 +378,46 @@ output_get_rr_modes(struct xwl_output *xwl_output,
     RRModePtr *rr_modes;
     int i;
 
-    rr_modes = xallocarray(ARRAY_SIZE(xwl_output_fake_modes) + 1, sizeof(RRModePtr));
+    rr_modes = xallocarray(ARRAY_SIZE(xwl_output_fake_modes) + 2, sizeof(RRModePtr));
     if (!rr_modes)
         goto err;
 
-    /* Add actual output mode */
-    rr_modes[0] = xwayland_cvt(width, height, xwl_output->refresh / 1000.0, 0, 0);
-    if (!rr_modes[0])
+    *count = 0;
+
+    if (xwl_screen_has_resolution_change_emulation(xwl_screen) &&
+        (width > xwl_output->mode_width ||
+         (width == xwl_output->mode_width && height > xwl_output->mode_height))) {
+        /* Add native output mode as preferred */
+        rr_modes[0] = xwayland_cvt(xwl_output->mode_width, xwl_output->mode_height,
+                                   xwl_output->refresh / 1000.0, 0, 0);
+        if (!rr_modes[0])
+            goto err;
+
+        *count = 1;
+    }
+
+    /* Add logical output mode */
+    rr_modes[*count] = xwayland_cvt(width, height, xwl_output->refresh / 1000.0, 0, 0);
+    if (!rr_modes[*count])
         goto err;
 
-    *count = 1;
+    (*count)++;
 
     if (!xwl_screen_has_resolution_change_emulation(xwl_screen) && !xwl_screen->force_xrandr_emulation)
         return rr_modes;
 
     /* Add fake modes */
     for (i = 0; i < ARRAY_SIZE(xwl_output_fake_modes); i++) {
-        /* Skip actual output mode, already added */
+        /* Skip logical output mode, already added */
         if (xwl_output_fake_modes[i][0] == width &&
             xwl_output_fake_modes[i][1] == height)
             continue;
 
+        /* Skip native output mode, already added */
+        if (xwl_output_fake_modes[i][0] == xwl_output->mode_width &&
+            xwl_output_fake_modes[i][1] == xwl_output->mode_height)
+            continue;
+
         /* Skip modes which are too big, avoid downscaling */
         if (xwl_output_fake_modes[i][0] > width ||
             xwl_output_fake_modes[i][1] > height)
@@ -660,6 +679,7 @@ apply_output_change(struct xwl_output *xwl_output)
     struct xwl_output *it;
     int logical_width, logical_height, count, has_this_output = 0;
     RRModePtr *randr_modes;
+    RRModePtr default_mode;
 
     /* Clear out the "done" received flags */
     xwl_output->wl_output_done = FALSE;
@@ -670,8 +690,15 @@ apply_output_change(struct xwl_output *xwl_output)
     if (xwl_output->randr_output) {
         /* Build a fresh modes array using the current refresh rate */
         randr_modes = output_get_rr_modes(xwl_output, logical_width, logical_height, &count);
+
+        if (randr_modes[0]->mode.width == logical_width &&
+            randr_modes[0]->mode.height == logical_height)
+            default_mode = randr_modes[0];
+        else
+            default_mode = randr_modes[1];
+
         RROutputSetModes(xwl_output->randr_output, randr_modes, count, 1);
-        RRCrtcNotify(xwl_output->randr_crtc, randr_modes[0],
+        RRCrtcNotify(xwl_output->randr_crtc, default_mode,
                      xwl_output->logical_x, xwl_output->logical_y,
                      xwl_output->rotation, NULL, 1, &xwl_output->randr_output);
         /* RROutputSetModes takes ownership of the passed in modes, so we only