Re: [yocto] weston 13.0.1 assert fail #scarthgap

[Gyorgy Sarvari <skandigraun@gmail.com>]

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On 11/25/25 16:39, Jarno via Lists.Yoctoproject.Org wrote:
> git rev-parse HEAD
> 5240b5c200e594b494a7f1a8f9d81e7c09bc8939
>  
> MACHINE=raspberrypi4-64 bitbake -e weston | grep ^SRC_URI
> SRC_URI="file://0001-libweston-tools-Include-libgen.h-for-basename-signat.patch
> file://0001-vnc-Allow-neatvnc-in-version-0.8.0.patch file://weston.png
> file://weston.desktop file://xwayland.weston-start
> file://systemd-notify.weston-start
> file://0001-Adapt-weston-to-64-bit-plane-IDs.patch"
>  
> After build and flash same behaviour persist.

Hmmm... this is strange, I tested using the same hw (rpi4-64) with the
same revision, and just verified the patch again earlier today with both
6.6 and 6.12 kernels.

I have attached another patch, which is similar to the one in the
repository. You can just overwrite
0001-Adapt-weston-to-64-bit-plane-IDs.patch in meta-raspberrypi with
this (as a test, revert it afterwards), and build a new image. 

Does it crash also?

If yes, do you get the same backtrace, or is it different?


>  
> core dump:
>  
> #4  0x0000007f93ba55a0 in __assert_fail_base
>     (fmt=0x7f93cbdb70 "%s%s%s:%u: %s%sAssertion `%s' failed.\n%n",
> assertion=assertion@entry=0x7f92e6f420 "fb",
> file=file@entry=0x7f92e6ead0
> "/usr/src/debug/weston/13.0.1/libweston/backend-drm/state-propose.c",
> line=line@entry=506, function=function@entry=0x7f92e70ab0
> <__PRETTY_FUNCTION__.5> "drm_output_find_plane_for_view") at assert.c:96
> #5  0x0000007f93ba5624 in __assert_fail
>     (assertion=assertion@entry=0x7f92e6f420 "fb",
> file=file@entry=0x7f92e6ead0
> "/usr/src/debug/weston/13.0.1/libweston/backend-drm/state-propose.c",
> line=line@entry=506, function=function@entry=0x7f92e70ab0
> <__PRETTY_FUNCTION__.5> "drm_output_find_plane_for_view") at assert.c:105
> #6  0x0000007f92e6784c in drm_output_find_plane_for_view
>     (current_lowest_zpos=18446744073709551615, scanout_state=0x0,
> mode=DRM_OUTPUT_PROPOSE_STATE_PLANES_ONLY, pnode=0x55812dab90,
> state=0x558137fc70) at
> /usr/src/debug/weston/13.0.1/libweston/backend-drm/state-propose.c:506
>  
>  

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From b66f14a812c96b92a83cec4bb637c1b982168d24 Mon Sep 17 00:00:00 2001
From: Gyorgy Sarvari <skandigraun@gmail.com>
Date: Sat, 22 Nov 2025 09:00:39 +0100
Subject: [PATCH] backend-drm: support 64-bit plane_mask

This change was prompted by a recent change in the Raspberry Pi
kernel[1], which has changed the plane_mask width to 64-bit in
their drm driver. Due to this weston behaved in an erratic way
on Raspberry Pi devices - usually this manifested in a crash
immediatelly when the mouse is moved (which was worked around
since by removing a failing assert[2]).

This change adapts libweston to accept 64-bit wide plane masks.

NB: the mentioned kernel change seems to be Raspberry Pi specific,
and there are no signs of it being mainlined.

[1]: https://github.com/raspberrypi/linux/commit/8181e682d6f4ef209845ec24f0a1eb37764d6731
[2]: https://gitlab.freedesktop.org/wayland/weston/-/issues/1039

Upstream-Status: Pending

Signed-off-by: Gyorgy Sarvari <skandigraun@gmail.com>
---
 libweston/backend-drm/drm-internal.h  |  2 +-
 libweston/backend-drm/drm.c           |  4 ++++
 libweston/backend-drm/fb.c            |  2 +-
 libweston/backend-drm/state-propose.c | 10 +++++-----
 4 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/libweston/backend-drm/drm-internal.h b/libweston/backend-drm/drm-internal.h
index e008a8d1..305abbce 100644
--- a/libweston/backend-drm/drm-internal.h
+++ b/libweston/backend-drm/drm-internal.h
@@ -410,7 +410,7 @@ struct drm_fb {
 	int width, height;
 	int fd;
 
-	uint32_t plane_mask;
+	uint64_t plane_mask;
 
 	/* Used by gbm fbs */
 	struct gbm_bo *bo;
diff --git a/libweston/backend-drm/fb.c b/libweston/backend-drm/fb.c
index 350aaf60..7baaa1b9 100644
--- a/libweston/backend-drm/fb.c
+++ b/libweston/backend-drm/fb.c
@@ -760,7 +760,7 @@ drm_fb_get_from_paint_node(struct drm_output_state *state,
 			continue;
 
 		if (drm_fb_compatible_with_plane(fb, plane))
-			fb->plane_mask |= 1 << (plane->plane_idx);
+			fb->plane_mask |= 1UL << (plane->plane_idx);
 	}
 	if (fb->plane_mask == 0) {
 		drm_fb_unref(fb);
--- ./libweston/backend-drm/state-propose.c.oeig	2025-11-25 12:49:15.280259892 +0100
+++ ./libweston/backend-drm/state-propose.c	2025-11-25 12:50:08.247823256 +0100
@@ -393,7 +393,7 @@
 	struct drm_fb *fb = NULL;
 
 	bool view_matches_entire_output, scanout_has_view_assigned;
-	uint32_t possible_plane_mask = 0;
+	uint64_t possible_plane_mask = 0;
 
 	pnode->try_view_on_plane_failure_reasons = FAILURE_REASONS_NONE;
 
@@ -437,7 +437,7 @@
 			return NULL;
 		}
 
-		possible_plane_mask = (1 << output->cursor_plane->plane_idx);
+		possible_plane_mask = (1UL << output->cursor_plane->plane_idx);
 	} else {
 		if (mode == DRM_OUTPUT_PROPOSE_STATE_RENDERER_ONLY) {
 			drm_debug(b, "\t\t\t\t[view] not assigning view %p "
@@ -450,7 +450,7 @@
 				continue;
 
 			if (drm_paint_node_transform_supported(pnode, plane))
-				possible_plane_mask |= 1 << plane->plane_idx;
+				possible_plane_mask |= 1UL << plane->plane_idx;
 		}
 
 		if (!possible_plane_mask) {
@@ -483,10 +483,10 @@
 		if (possible_plane_mask == 0)
 			break;
 
-		if (!(possible_plane_mask & (1 << plane->plane_idx)))
+		if (!(possible_plane_mask & (1UL << plane->plane_idx)))
 			continue;
 
-		possible_plane_mask &= ~(1 << plane->plane_idx);
+		possible_plane_mask &= ~(1UL << plane->plane_idx);
 
 		switch (plane->type) {
 		case WDRM_PLANE_TYPE_CURSOR:
--- ./libweston/backend-drm/state-propose.c.orig	2025-11-25 13:26:58.173810837 +0100
+++ ./libweston/backend-drm/state-propose.c	2025-11-25 13:28:21.576255290 +0100
@@ -43,6 +43,8 @@
 #include "presentation-time-server-protocol.h"
 #include "linux-dmabuf-unstable-v1-server-protocol.h"
 
+#define MAX_PLANE_NR 64
+
 enum drm_output_propose_state_mode {
 	DRM_OUTPUT_PROPOSE_STATE_MIXED, /**< mix renderer & planes */
 	DRM_OUTPUT_PROPOSE_STATE_RENDERER_ONLY, /**< only assign to renderer & cursor */
@@ -395,6 +397,8 @@
 	bool view_matches_entire_output, scanout_has_view_assigned;
 	uint64_t possible_plane_mask = 0;
 
+	assert(output->cursor_plane->plane_idx < MAX_PLANE_NR);
+
 	pnode->try_view_on_plane_failure_reasons = FAILURE_REASONS_NONE;
 
 	/* check view for valid buffer, doesn't make sense to even try */
@@ -449,6 +453,7 @@
 			if (plane->type == WDRM_PLANE_TYPE_CURSOR)
 				continue;
 
+			assert(plane->plane_idx < MAX_PLANE_NR);
 			if (drm_paint_node_transform_supported(pnode, plane))
 				possible_plane_mask |= 1UL << plane->plane_idx;
 		}