diff --git a/build.py b/build.py
index 928784b49..c55209a82 100755
--- a/build.py
+++ b/build.py
@@ -488,7 +488,7 @@ def _assert_so_has_egl(so_path):
         with open(so_path, 'rb') as f:
             blob = f.read()
     except OSError as err:
-        raise Exception(f'cannot read the built libdrmtap at {so_path}: {err}')
+        raise Exception(f'cannot read the built libdrmtap at {so_path}: {err}') from err
     missing = [m for m in (b'libEGL.so.1', b'eglCreateImageKHR') if m not in blob]
     if missing:
         raise Exception(
diff --git a/src/server/wayland.rs b/src/server/wayland.rs
index 40869903d..f08a19717 100644
--- a/src/server/wayland.rs
+++ b/src/server/wayland.rs
@@ -457,25 +457,37 @@ pub(super) fn get_capturer_for_display(
                     None => (None, false),
                 };
                 if let Some(advertised) = advertised {
-                    // The advertised DRM geometry is PHYSICAL while the PipeWire rect is the
-                    // compositor's LOGICAL size (try_fix_logical_size), so on a scaled output the
-                    // two sizes legitimately disagree (2880x1800 vs 1440x900) even when the stream
-                    // IS this display. On a single-display host the whole-desktop stream is this
-                    // display by construction, so only the position has to agree there; comparing
-                    // the physical size too rejected the one valid fallback and restart-looped the
-                    // display instead of degrading. On a multi-monitor host the size check stays:
-                    // it is what tells one connector apart from the full-desktop rect.
+                    // Compare LOGICAL against LOGICAL. The advertised DRM geometry carries the
+                    // PHYSICAL mode plus the compositor scale (augment_with_wayland_geometry sets
+                    // x/y/scale and deliberately leaves width/height physical), while the PipeWire
+                    // rect is already logical (try_fix_logical_size). Comparing the two raw made a
+                    // scaled output disagree with itself -- 2880x1800 against 1440x900 -- and the
+                    // guard then rejected a portal stream that really was this display, leaving it
+                    // advertised offline instead of degrading to PipeWire.
+                    //
+                    // The size check itself stays, because on a multi-monitor host it is what
+                    // tells a single connector apart from the whole-desktop rect the portal
+                    // usually exposes. On a single-display host that rect IS this display by
+                    // construction, so only the position has to agree.
+                    let scale = if advertised.scale > 0.0 {
+                        advertised.scale
+                    } else {
+                        1.0
+                    };
+                    let logical_w = (advertised.width as f64 / scale).round() as usize;
+                    let logical_h = (advertised.height as f64 / scale).round() as usize;
                     let consistent = advertised.x == rect.0 .0
                         && advertised.y == rect.0 .1
-                        && (single_display
-                            || (advertised.width as usize == rect.1
-                                && advertised.height as usize == rect.2));
+                        && (single_display || (logical_w == rect.1 && logical_h == rect.2));
                     if !consistent {
+                        // Report the LOGICAL numbers, the ones actually compared, so the message
+                        // does not look like a mismatch of quantities that were never expected to
+                        // match on a scaled output.
                         bail!(
-                            "drm display {} demoted with no geometry-consistent PipeWire stream (advertised {}x{}+{}+{} vs stream {}x{}+{}+{}); advertised offline",
+                            "drm display {} demoted with no geometry-consistent PipeWire stream (advertised {}x{} logical +{}+{} vs stream {}x{}+{}+{}); advertised offline",
                             display_idx,
-                            advertised.width,
-                            advertised.height,
+                            logical_w,
+                            logical_h,
                             advertised.x,
                             advertised.y,
                             rect.1,