kms/impl: Dont discard page flips in callback when failed up front

If posting an update resulted in an immediate error, don't communicate
this failure using the page flip feedback callbacks, but directly as a
return value.

This makes it possible for the direct client buffer scanout path not to
pass around flags triggering this behavior, meaning we can handle such
direct scanouts better.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1488>

src/backends/native/meta-kms-impl-device-simple.c

@@ -814,23 +814,6 @@ process_page_flip (MetaKmsImplDevice  *impl_device,
   return TRUE;
 }
 
-static void
-discard_page_flip (MetaKmsImplDevice *impl_device,
-                   MetaKmsUpdate     *update,
-                   MetaKmsPageFlip   *page_flip)
-{
-  MetaKmsCrtc *crtc;
-  MetaKmsPageFlipData *page_flip_data;
-
-  crtc = page_flip->crtc;
-  page_flip_data = meta_kms_page_flip_data_new (impl_device,
-                                                crtc,
-                                                page_flip->feedback,
-                                                page_flip->user_data);
-  meta_kms_page_flip_data_discard_in_impl (page_flip_data, NULL);
-  meta_kms_page_flip_data_unref (page_flip_data);
-}
-
 static gboolean
 process_entries (MetaKmsImplDevice  *impl_device,
                  MetaKmsUpdate      *update,
@@ -1029,7 +1012,6 @@ meta_kms_impl_device_simple_process_update (MetaKmsImplDevice *impl_device,
 {
   GError *error = NULL;
   GList *failed_planes;
-  GList *l;
 
   if (!process_entries (impl_device,
                         update,
@@ -1073,16 +1055,6 @@ err_planes_not_assigned:
   failed_planes = generate_all_failed_feedbacks (update);
 
 err_planes_assigned:
-  for (l = meta_kms_update_get_page_flips (update); l; l = l->next)
-    {
-      MetaKmsPageFlip *page_flip = l->data;
-
-      if (page_flip->flags & META_KMS_PAGE_FLIP_FLAG_NO_DISCARD_FEEDBACK)
-        continue;
-
-      discard_page_flip (impl_device, update, page_flip);
-    }
-
   return meta_kms_feedback_new_failed (failed_planes, error);
 }
 

src/backends/native/meta-kms-update-private.h

@@ -90,7 +90,6 @@ typedef struct _MetaKmsPageFlip
 {
   MetaKmsCrtc *crtc;
   const MetaKmsPageFlipFeedback *feedback;
-  MetaKmsPageFlipFlag flags;
   gpointer user_data;
 } MetaKmsPageFlip;
 

src/backends/native/meta-kms-update.c

@@ -325,7 +325,6 @@ void
 meta_kms_update_page_flip (MetaKmsUpdate                 *update,
                            MetaKmsCrtc                   *crtc,
                            const MetaKmsPageFlipFeedback *feedback,
-                           MetaKmsPageFlipFlag            flags,
                            gpointer                       user_data)
 {
   MetaKmsPageFlip *page_flip;
@@ -337,7 +336,6 @@ meta_kms_update_page_flip (MetaKmsUpdate                 *update,
   *page_flip = (MetaKmsPageFlip) {
     .crtc = crtc,
     .feedback = feedback,
-    .flags = flags,
     .user_data = user_data,
   };
 

src/backends/native/meta-kms-update.h

@@ -42,12 +42,6 @@ typedef enum _MetaKmsAssignPlaneFlag
   META_KMS_ASSIGN_PLANE_FLAG_FB_UNCHANGED = 1 << 0,
 } MetaKmsAssignPlaneFlag;
 
-typedef enum _MetaKmsPageFlipFlag
-{
-  META_KMS_PAGE_FLIP_FLAG_NONE = 0,
-  META_KMS_PAGE_FLIP_FLAG_NO_DISCARD_FEEDBACK = 1 << 0,
-} MetaKmsPageFlipFlag;
-
 struct _MetaKmsPageFlipFeedback
 {
   void (* flipped) (MetaKmsCrtc  *crtc,
@@ -125,7 +119,6 @@ MetaKmsPlaneAssignment * meta_kms_update_unassign_plane (MetaKmsUpdate *update,
 void meta_kms_update_page_flip (MetaKmsUpdate                 *update,
                                 MetaKmsCrtc                   *crtc,
                                 const MetaKmsPageFlipFeedback *feedback,
-                                MetaKmsPageFlipFlag            flags,
                                 gpointer                       user_data);
 
 void meta_kms_update_set_custom_page_flip (MetaKmsUpdate             *update,

src/backends/native/meta-renderer-native.c

@@ -1250,10 +1250,9 @@ queue_dummy_power_save_page_flip (CoglOnscreen *onscreen)
 }
 
 static void
-meta_onscreen_native_flip_crtc (CoglOnscreen        *onscreen,
+meta_onscreen_native_flip_crtc (CoglOnscreen     *onscreen,
-                                MetaRendererView    *view,
+                                MetaRendererView *view,
-                                MetaCrtc            *crtc,
+                                MetaCrtc         *crtc)
-                                MetaKmsPageFlipFlag  flags)
 {
   CoglOnscreenEGL *onscreen_egl = onscreen->winsys;
   MetaOnscreenNative *onscreen_native = onscreen_egl->platform;
@@ -1305,7 +1304,6 @@ meta_onscreen_native_flip_crtc (CoglOnscreen        *onscreen,
   meta_kms_update_page_flip (kms_update,
                              meta_crtc_kms_get_kms_crtc (crtc_kms),
                              &page_flip_feedback,
-                             flags,
                              g_object_ref (view));
 }
 
@@ -1348,8 +1346,7 @@ meta_onscreen_native_set_crtc_mode (CoglOnscreen              *onscreen,
 }
 
 static void
-meta_onscreen_native_flip_crtcs (CoglOnscreen        *onscreen,
+meta_onscreen_native_flip_crtcs (CoglOnscreen *onscreen)
-                                 MetaKmsPageFlipFlag  flags)
 {
   CoglOnscreenEGL *onscreen_egl = onscreen->winsys;
   MetaOnscreenNative *onscreen_native = onscreen_egl->platform;
@@ -1358,8 +1355,7 @@ meta_onscreen_native_flip_crtcs (CoglOnscreen        *onscreen,
   COGL_TRACE_BEGIN_SCOPED (MetaOnscreenNativeFlipCrtcs,
                            "Onscreen (flip CRTCs)");
 
-  meta_onscreen_native_flip_crtc (onscreen, view, onscreen_native->crtc,
+  meta_onscreen_native_flip_crtc (onscreen, view, onscreen_native->crtc);
-                                  flags);
 }
 
 static gboolean
@@ -1988,7 +1984,7 @@ meta_onscreen_native_swap_buffers_with_damage (CoglOnscreen  *onscreen,
   if (power_save_mode == META_POWER_SAVE_ON)
     {
       ensure_crtc_modes (onscreen);
-      meta_onscreen_native_flip_crtcs (onscreen, META_KMS_PAGE_FLIP_FLAG_NONE);
+      meta_onscreen_native_flip_crtcs (onscreen);
     }
   else
     {
@@ -2192,8 +2188,7 @@ meta_onscreen_native_direct_scanout (CoglOnscreen   *onscreen,
   g_set_object (&onscreen_native->gbm.next_fb, META_DRM_BUFFER (scanout));
 
   ensure_crtc_modes (onscreen);
-  meta_onscreen_native_flip_crtcs (onscreen,
+  meta_onscreen_native_flip_crtcs (onscreen);
-                                   META_KMS_PAGE_FLIP_FLAG_NO_DISCARD_FEEDBACK);
 
   kms_crtc = meta_crtc_kms_get_kms_crtc (META_CRTC_KMS (onscreen_native->crtc));
   kms_device = meta_kms_crtc_get_device (kms_crtc);