Commit 860e748bddcc ("drm: ensure blend mode supported if
pixel format with alpha exposed") added validation that warns when a
plane exposes an alpha format without a pixel blend mode property. PL111
exposes several such formats but does not attach the property.
The PL110/PL111 controller scans out a single framebuffer and does not
blend its alpha channel with a background. Advertise
DRM_MODE_BLEND_PIXEL_NONE to match the existing hardware behavior.
With panic_on_warn enabled, this warning prevents the syzkaller
vexpress-a15 manager from booting. The change was tested on current
master with QEMU 10 and the existing production DTB; the guest reached
sshd and returned an SSH banner.
Fixes: 860e748bddcc ("drm: ensure blend mode supported if pixel format with
alpha exposed")
Link: https://github.com/google/syzkaller/issues/7805
Signed-off-by: Roshan Kumar <[email protected]>
---
drivers/gpu/drm/pl111/pl111_display.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/gpu/drm/pl111/pl111_display.c
b/drivers/gpu/drm/pl111/pl111_display.c
index 5d10bc5..758b297 100644
--- a/drivers/gpu/drm/pl111/pl111_display.c
+++ b/drivers/gpu/drm/pl111/pl111_display.c
@@ -15,6 +15,7 @@
#include <linux/media-bus-format.h>
#include <linux/of_graph.h>
+#include <drm/drm_blend.h>
#include <drm/drm_fb_dma_helper.h>
#include <drm/drm_fourcc.h>
#include <drm/drm_framebuffer.h>
@@ -596,5 +597,10 @@ int pl111_display_init(struct drm_device *drm)
if (ret)
return ret;
+ ret = drm_plane_create_blend_mode_property(&priv->pipe.plane,
+
BIT(DRM_MODE_BLEND_PIXEL_NONE));
+ if (ret)
+ return ret;
+
return 0;
}
--
2.43.0
