Cycles: Disable the render time pass for GPU

Also, extend the description in the UI.

Pull Request: https://projects.blender.org/blender/blender/pulls/147054

intern/cycles/blender/addon/engine.py

@@ -220,7 +220,9 @@ def list_render_passes(scene, srl):
     if crl.pass_debug_sample_count:
         yield ("Debug Sample Count", "X", 'VALUE')
     if crl.pass_render_time:
-        yield ("Render Time", "X", 'VALUE')
+        # Only yield the pass if rendering on CPU
+        if scene.cycles.device == 'CPU':
+            yield ("Render Time", "X", "VALUE")
 
     # Cryptomatte passes.
     # NOTE: Name channels are lowercase RGBA so that compression rules check in OpenEXR DWA code

intern/cycles/blender/addon/properties.py

@@ -383,6 +383,7 @@ class CyclesRenderSettings(bpy.types.PropertyGroup):
         description="Device to use for rendering",
         items=enum_devices,
         default='CPU',
+        update=update_render_passes,
     )
     shading_system: BoolProperty(
         name="Open Shading Language",
@@ -1486,7 +1487,7 @@ class CyclesRenderLayerSettings(bpy.types.PropertyGroup):
     )
     pass_render_time: BoolProperty(
         name="Render Time",
-        description="Pass containing an estimate for how long each pixel took to render",
+        description="Reports time per pixel in milliseconds. Supported only on CPU render devices",
         default=False,
         update=update_render_passes,
     )

intern/cycles/blender/addon/ui.py

@@ -1034,7 +1034,13 @@ class CYCLES_RENDER_PT_passes_data(CyclesButtonsPanel, Panel):
 
         col = layout.column(heading="Debug", align=True)
         col.prop(cycles_view_layer, "pass_debug_sample_count", text="Sample Count")
-        col.prop(cycles_view_layer, "pass_render_time", text="Render Time")
+
+        # Render Time pass - disabled for GPU devices
+        scene = context.scene
+        cscene = scene.cycles
+        row = col.row()
+        row.enabled = (cscene.device == 'CPU')
+        row.prop(cycles_view_layer, "pass_render_time", text="Render Time")
 
         layout.prop(view_layer, "pass_alpha_threshold")