On 8/25/26 7:54 AM, Roshan Kumar wrote:
> 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;
> +
Hello,
Thank you! Looks good to me from the blend-mode requirements
perspective. But I'm not familiar with this driver. So, with this caveat:
Reviewed-by: Leandro Ribeiro <[email protected]>
> return 0;
> }
--
Leandro Ribeiro
