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onscreen/native: Account for all posted frames

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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: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/4334>
This commit is contained in:
Jonas Ådahl 2025-03-13 23:43:25 +08:00 committed by Bruce Leidl
parent 48cb47425b
commit a68a06cfc3
1 changed files with 16 additions and 3 deletions
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19
src/backends/native/meta-onscreen-native.c
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@ -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);
}