From 23dfcba633f19762e1e75aef737a5b891c59f77b Mon Sep 17 00:00:00 2001
From: John Studnicka <contact@zentec.dev>
Date: Sun, 25 Jan 2026 03:31:38 -0700
Subject: [PATCH] modesetting: Fall back to SW cursor for OOB dims

Signed-off-by: John Studnicka <contact@zentec.dev>
---
 .../video/modesetting/drmmode_display.c       | 24 ++++++++++++++-----
 .../video/modesetting/drmmode_display.h       |  1 +
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/hw/xfree86/drivers/video/modesetting/drmmode_display.c b/hw/xfree86/drivers/video/modesetting/drmmode_display.c
index b97e0df9c..ac285d09a 100644
--- a/hw/xfree86/drivers/video/modesetting/drmmode_display.c
+++ b/hw/xfree86/drivers/video/modesetting/drmmode_display.c
@@ -2001,7 +2001,6 @@ drmmode_load_cursor_argb_check(xf86CrtcPtr crtc, CARD32 *image)
     drmmode_crtc_private_ptr drmmode_crtc = crtc->driver_private;
     modesettingPtr ms = modesettingPTR(crtc->scrn);
     CursorPtr cursor = xf86CurrentCursor(crtc->scrn->pScreen);
-    int i;
 
     if (drmmode_crtc->cursor_up) {
         /* we probe the cursor so late, because we want to make sure that
@@ -2013,9 +2012,10 @@ drmmode_load_cursor_argb_check(xf86CrtcPtr crtc, CARD32 *image)
     drmmode_cursor_rec drmmode_cursor = drmmode_crtc->cursor;
 
     /* Find the most compatiable size. */
-    for (i = 0; i < drmmode_cursor.num_dimensions; i++)
+    int idx;
+    for (idx = 0; idx < drmmode_cursor.num_dimensions; idx++)
     {
-        drmmode_cursor_dim_rec dimensions = drmmode_cursor.dimensions[i];
+        drmmode_cursor_dim_rec dimensions = drmmode_cursor.dimensions[idx];
 
         if (dimensions.width >= cursor->bits->width &&
             dimensions.height >= cursor->bits->height) {
@@ -2023,11 +2023,23 @@ drmmode_load_cursor_argb_check(xf86CrtcPtr crtc, CARD32 *image)
         }
     }
 
-    const int cursor_pitch = drmmode_cursor_get_pitch(drmmode_crtc, i);
+    if (idx >= drmmode_cursor.num_dimensions) {
+        /* No compatible hardware cursor size; fall back to software cursor. */
+        if (!drmmode_crtc->cursor_dim_fallback_warned) {
+            xf86DrvMsg(crtc->scrn->scrnIndex, X_WARNING,
+                       "No compatible hardware cursor size for %dx%d; "
+                       "falling back to software cursor\n",
+                       cursor->bits->width, cursor->bits->height);
+            drmmode_crtc->cursor_dim_fallback_warned = TRUE;
+        }
+        return FALSE;
+    }
+
+    const int cursor_pitch = drmmode_cursor_get_pitch(drmmode_crtc, idx);
 
     /* Get the resolution of the cursor. */
-    int cursor_width  = drmmode_cursor.dimensions[i].width;
-    int cursor_height = drmmode_cursor.dimensions[i].height;
+    int cursor_width  = drmmode_cursor.dimensions[idx].width;
+    int cursor_height = drmmode_cursor.dimensions[idx].height;
 
     /* Get the size of the cursor image buffer */
     int image_width  = ms->cursor_image_width;
diff --git a/hw/xfree86/drivers/video/modesetting/drmmode_display.h b/hw/xfree86/drivers/video/modesetting/drmmode_display.h
index 2d12012e9..4e0907871 100644
--- a/hw/xfree86/drivers/video/modesetting/drmmode_display.h
+++ b/hw/xfree86/drivers/video/modesetting/drmmode_display.h
@@ -257,6 +257,7 @@ typedef struct {
     int old_pitch;
 
     Bool cursor_probed;
+    Bool cursor_dim_fallback_warned;
 
     int* cursor_pitches;
 } drmmode_crtc_private_rec, *drmmode_crtc_private_ptr;