(CC-ed Fei Shao)
On Thu, Jul 18, 2024 at 4:24 PM AngeloGioacchino Del Regno
<angelogioacchino.delregno@xxxxxxxxxxxxx> wrote:
>
> Hardware-speaking, there is no feature-reduced cursor specific
> plane, so this driver reserves the last all Overlay plane as a
> Cursor plane, but sets the maximum cursor width/height to the
> maximum value that the full overlay plane can use.
>
> While this could be ok, it raises issues with common userspace
> using libdrm (especially Mutter, but other compositors too) which
> will crash upon performing allocations and/or using said cursor
> plane.
>
> Reduce the maximum width/height for the cursor to 512x512 pixels,
> value taken from IGT's maximum cursor size test, which succeeds.
>
> Fixes: a4c9410b31ca ("drm/mediatek: Set DRM mode configs accordingly")
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/mediatek/mtk_drm_drv.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> index 6f0b415a978d..b96763664c4f 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> @@ -540,8 +540,8 @@ static int mtk_drm_kms_init(struct drm_device *drm)
> }
>
> /* IGT will check if the cursor size is configured */
> - drm->mode_config.cursor_width = drm->mode_config.max_width;
> - drm->mode_config.cursor_height = drm->mode_config.max_height;
> + drm->mode_config.cursor_width = 512;
> + drm->mode_config.cursor_height = 512;
Fei already did the same (?) workaround downstream just recently.
OOTH, Intel recently added a feature for enumerating "suggested"
cursor sizes. See https://patchwork.freedesktop.org/patch/583299/
Not sure if other compositors will end up using it or not.
ChenYu
> /* Use OVL device for all DMA memory allocations */
> crtc = drm_crtc_from_index(drm, 0);
> --
> 2.45.2
>
