Val Packett
1269a73318
As this was recently applied upstream, apply to the forked package Link: https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/4850 Link: https://gitlab.alpinelinux.org/alpine/aports/-/commit/732334134c9677994d622eb90cef9facd0fe47d9 Part-of: <https://gitlab.postmarketos.org/postmarketOS/pmaports/-/merge_requests/7909>
136 lines
5.5 KiB
Diff
136 lines
5.5 KiB
Diff
Patch-Source: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/4850> (merged)
|
|
---
|
|
From 6f7b463b1d2582f9caf17a20ef38c7c7b40528ea Mon Sep 17 00:00:00 2001
|
|
From: Stephan Gerhold <stephan@gerhold.net>
|
|
Date: Sun, 11 Jan 2026 18:13:24 +0100
|
|
Subject: [PATCH] crtc/kms: Prevent directly switching planes across CRTCs
|
|
|
|
The DRM Atomic API does not allow switching planes from one CRTC to another
|
|
CRTC in a single commit, see e.g. the plane_switching_crtc() function in
|
|
the Linux kernel source code [1] and commit f8aeb41c4b7e ("drm/atomic:
|
|
refuse changing CRTC for planes directly") inside the Linux kernel [2]. To
|
|
switch a plane from one CRTC to another, the plane must first be unassigned
|
|
in one commit and then re-enabled as part of another commit.
|
|
|
|
Currently, mutter re-assigns CRTCs and planes arbitrarily during monitor
|
|
reconfiguration and applies the result as part of a single commit. With
|
|
this approach, if an active plane ends up getting assigned to another CRTC,
|
|
all subsequent commits for that plane will fail and the affected screens
|
|
are effectively frozen until the previous plane assignment (usually the old
|
|
monitor configuration) is restored. On hardware that allows assigning
|
|
planes to arbitrary CRTCs, this problem usually happens when disabling a
|
|
monitor: mutter may try to switch planes from the disabled CRTC to another
|
|
enabled CRTC and subsequent atomic commits will fail (see #4399).
|
|
|
|
Avoid this error by refusing to re-assign any currently assigned plane,
|
|
similar to the existing check for leased CRTCs. Reuse already assigned
|
|
planes for CRTCs if possible.
|
|
|
|
This new approach solves the problem for hardware that has sufficient
|
|
planes for all CRTCs. More complex changes would be needed if a
|
|
reconfiguration would really require switching planes from one CRTC to
|
|
another. In this case, the reconfiguration would need to be split into two
|
|
separate commits.
|
|
|
|
[1]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/drm_atomic.c?h=v6.18#n571
|
|
[2]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f8aeb41c4b7e9de0a4df4ed1ba78cd6ee5c87281
|
|
|
|
Fixes: cc7bca073 ("crtc/kms: Dynamically assign primary and cursor planes")
|
|
Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/4399
|
|
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/4850>
|
|
---
|
|
src/backends/native/meta-crtc-kms.c | 49 ++++++++++++++++++++++++++---
|
|
1 file changed, 44 insertions(+), 5 deletions(-)
|
|
|
|
diff --git a/src/backends/native/meta-crtc-kms.c b/src/backends/native/meta-crtc-kms.c
|
|
index 8082c4a2e64..f65ca5607f9 100644
|
|
--- a/src/backends/native/meta-crtc-kms.c
|
|
+++ b/src/backends/native/meta-crtc-kms.c
|
|
@@ -260,10 +260,27 @@ is_plane_assigned (MetaKmsPlane *plane,
|
|
return FALSE;
|
|
}
|
|
|
|
+static MetaKmsPlane *
|
|
+crtc_assigned_plane (MetaCrtcKms *crtc_kms,
|
|
+ MetaKmsPlaneType kms_plane_type)
|
|
+{
|
|
+ switch (kms_plane_type)
|
|
+ {
|
|
+ case META_KMS_PLANE_TYPE_PRIMARY:
|
|
+ return crtc_kms->assigned_primary_plane;
|
|
+ case META_KMS_PLANE_TYPE_CURSOR:
|
|
+ return crtc_kms->assigned_cursor_plane;
|
|
+ case META_KMS_PLANE_TYPE_OVERLAY:
|
|
+ default:
|
|
+ g_assert_not_reached ();
|
|
+ }
|
|
+}
|
|
+
|
|
static gboolean
|
|
-is_plane_leased (MetaKmsDevice *kms_device,
|
|
+is_plane_active (MetaKmsDevice *kms_device,
|
|
MetaKmsPlane *kms_plane)
|
|
{
|
|
+ MetaKmsPlaneType kms_plane_type = meta_kms_plane_get_plane_type (kms_plane);
|
|
GList *l;
|
|
|
|
for (l = meta_kms_device_get_crtcs (kms_device); l; l = l->next)
|
|
@@ -271,9 +288,15 @@ is_plane_leased (MetaKmsDevice *kms_device,
|
|
MetaKmsCrtc *kms_crtc = l->data;
|
|
MetaCrtcKms *crtc_kms = meta_crtc_kms_from_kms_crtc (kms_crtc);
|
|
|
|
- if (meta_kms_crtc_is_leased (kms_crtc) &&
|
|
- crtc_kms->assigned_primary_plane == kms_plane)
|
|
- return TRUE;
|
|
+ if (crtc_assigned_plane (crtc_kms, kms_plane_type) == kms_plane)
|
|
+ {
|
|
+ meta_topic (META_DEBUG_KMS,
|
|
+ "Plane %u is currently active as %s for CRTC %u\n",
|
|
+ meta_kms_plane_get_id (kms_plane),
|
|
+ meta_kms_plane_type_to_string(kms_plane_type),
|
|
+ meta_kms_crtc_get_id (kms_crtc));
|
|
+ return TRUE;
|
|
+ }
|
|
}
|
|
|
|
return FALSE;
|
|
@@ -286,8 +309,18 @@ find_unassigned_plane (MetaCrtcKms *crtc_kms,
|
|
{
|
|
MetaKmsCrtc *kms_crtc = meta_crtc_kms_get_kms_crtc (crtc_kms);
|
|
MetaKmsDevice *kms_device = meta_kms_crtc_get_device (kms_crtc);
|
|
+ MetaKmsPlane *assigned_plane = crtc_assigned_plane (crtc_kms, kms_plane_type);
|
|
GList *l;
|
|
|
|
+ if (assigned_plane)
|
|
+ {
|
|
+ meta_topic (META_DEBUG_KMS, "Reusing assigned %s plane %u for CRTC %u\n",
|
|
+ meta_kms_plane_type_to_string (kms_plane_type),
|
|
+ meta_kms_plane_get_id (assigned_plane),
|
|
+ meta_kms_crtc_get_id (kms_crtc));
|
|
+ return assigned_plane;
|
|
+ }
|
|
+
|
|
for (l = meta_kms_device_get_planes (kms_device); l; l = l->next)
|
|
{
|
|
MetaKmsPlane *kms_plane = l->data;
|
|
@@ -302,9 +335,15 @@ find_unassigned_plane (MetaCrtcKms *crtc_kms,
|
|
crtc_assignments))
|
|
continue;
|
|
|
|
- if (is_plane_leased (kms_device, kms_plane))
|
|
+ if (is_plane_active (kms_device, kms_plane))
|
|
continue;
|
|
|
|
+ meta_topic (META_DEBUG_KMS,
|
|
+ "Plane %u is unassigned and can be used as %s for CRTC %u\n",
|
|
+ meta_kms_plane_get_id (kms_plane),
|
|
+ meta_kms_plane_type_to_string (kms_plane_type),
|
|
+ meta_kms_crtc_get_id (kms_crtc));
|
|
+
|
|
return kms_plane;
|
|
}
|
|
|
|
--
|
|
GitLab
|
|
|