From a68a06cfc3bea54da5f65b7b7db9b31beb74eb51 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Jonas=20=C3=85dahl?= Date: Thu, 13 Mar 2025 23:43:25 +0800 Subject: [PATCH] onscreen/native: Account for all posted frames The KMS thread handles updates posted asynchronously, but it expects to only handle one such frame in flight from the compositor at a time. That means that the triple buffering state tracking in MetaOncreen, that keeps track of posted frames and when they become presented, must also account for posted frames that doesn't contain an actual primary plane pixel buffer. This was not the case, causing MetaOnscreenNative to post multiple frames to the KMS thread, which wasn't handled gracefully in certain situations. Before the KMS thread grows real support for it's own queue of separate updates, make sure we keep the contract to the KMS thread in MetaOnscreenNative, and only submit at most one KMS update for each CRTC each cycle, even when there are no actual primary plane changes. v2: Properly handle frame tracking when when KMS update empty v3: In the page flip callback, only set the presented frame to frames that has buffers. This is needed on older kernels which doesn't have drmModeCloseFB() which would otherwise disable the CRTC when presented frame with an actual buffer would be replaced with an "empty" frame, causing the frame with the buffer to be released, with the buffer along with it. Part-of: --- src/backends/native/meta-onscreen-native.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/src/backends/native/meta-onscreen-native.c b/src/backends/native/meta-onscreen-native.c index 7ffcd7b7a..d8e4548d8 100644 --- a/src/backends/native/meta-onscreen-native.c +++ b/src/backends/native/meta-onscreen-native.c @@ -159,13 +159,22 @@ static void meta_onscreen_native_swap_drm_fb (CoglOnscreen *onscreen) { MetaOnscreenNative *onscreen_native = META_ONSCREEN_NATIVE (onscreen); + MetaFrameNative *frame_native; if (!onscreen_native->posted_frame) return; - g_clear_pointer (&onscreen_native->presented_frame, clutter_frame_unref); - onscreen_native->presented_frame = - g_steal_pointer (&onscreen_native->posted_frame); + frame_native = meta_frame_native_from_frame (onscreen_native->posted_frame); + if (!meta_frame_native_get_buffer (frame_native)) + { + g_clear_pointer (&onscreen_native->posted_frame, clutter_frame_unref); + } + else + { + g_clear_pointer (&onscreen_native->presented_frame, clutter_frame_unref); + onscreen_native->presented_frame = + g_steal_pointer (&onscreen_native->posted_frame); + } } static void @@ -1675,6 +1684,7 @@ maybe_post_next_frame (CoglOnscreen *onscreen) { kms_update = meta_frame_native_steal_kms_update (frame_native); post_nonprimary_plane_update (onscreen_native, frame, kms_update); + onscreen_native->posted_frame = clutter_frame_ref (frame); return; } @@ -2034,6 +2044,7 @@ finish_frame_result_feedback (const MetaKmsFeedback *kms_feedback, gpointer user_data) { CoglOnscreen *onscreen = COGL_ONSCREEN (user_data); + MetaOnscreenNative *onscreen_native = META_ONSCREEN_NATIVE (onscreen); const GError *error; CoglFrameInfo *frame_info; @@ -2059,6 +2070,7 @@ finish_frame_result_feedback (const MetaKmsFeedback *kms_feedback, frame_info->flags |= COGL_FRAME_INFO_FLAG_SYMBOLIC; meta_onscreen_native_notify_frame_complete (onscreen); + g_clear_pointer (&onscreen_native->posted_frame, clutter_frame_unref); } static const MetaKmsResultListenerVtable finish_frame_result_listener_vtable = { @@ -2131,6 +2143,7 @@ meta_onscreen_native_finish_frame (CoglOnscreen *onscreen, } post_nonprimary_plane_update (onscreen_native, frame, kms_update); + onscreen_native->posted_frame = clutter_frame_ref (frame); clutter_frame_set_result (frame, CLUTTER_FRAME_RESULT_PENDING_PRESENTED); }