drm/vmwgfx: Restore Guest-Backed only cursor plane support

The referenced fixes commit broke the cursor plane for configurations
which have Guest-Backed surfaces but no cursor MOB support.

Fixes: 9655441 ("drm/vmwgfx: Refactor cursor handling")
Signed-off-by: Ian Forbes <ian.forbes@broadcom.com>
Signed-off-by: Zack Rusin <zack.rusin@broadcom.com>
Link: https://patch.msgid.link/20251103201920.381503-1-ian.forbes@broadcom.com

Author: en4bz

drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c

@@ -100,8 +100,10 @@ vmw_cursor_update_type(struct vmw_private *vmw, struct vmw_plane_state *vps)
 	if (vmw->has_mob) {
 		if ((vmw->capabilities2 & SVGA_CAP2_CURSOR_MOB) != 0)
 			return VMW_CURSOR_UPDATE_MOB;
+		else
+			return VMW_CURSOR_UPDATE_GB_ONLY;
 	}
-
+	drm_warn_once(&vmw->drm, "Unknown Cursor Type!\n");
 	return VMW_CURSOR_UPDATE_NONE;
 }
 
@@ -139,6 +141,7 @@ static u32 vmw_cursor_mob_size(enum vmw_cursor_update_type update_type,
 {
 	switch (update_type) {
 	case VMW_CURSOR_UPDATE_LEGACY:
+	case VMW_CURSOR_UPDATE_GB_ONLY:
 	case VMW_CURSOR_UPDATE_NONE:
 		return 0;
 	case VMW_CURSOR_UPDATE_MOB:
@@ -623,6 +626,7 @@ int vmw_cursor_plane_prepare_fb(struct drm_plane *plane,
 		if (!surface || vps->cursor.legacy.id == surface->snooper.id)
 			vps->cursor.update_type = VMW_CURSOR_UPDATE_NONE;
 		break;
+	case VMW_CURSOR_UPDATE_GB_ONLY:
 	case VMW_CURSOR_UPDATE_MOB: {
 		bo = vmw_user_object_buffer(&vps->uo);
 		if (bo) {
@@ -737,6 +741,7 @@ void
 vmw_cursor_plane_atomic_update(struct drm_plane *plane,
 			       struct drm_atomic_state *state)
 {
+	struct vmw_bo *bo;
 	struct drm_plane_state *new_state =
 		drm_atomic_get_new_plane_state(state, plane);
 	struct drm_plane_state *old_state =
@@ -762,6 +767,15 @@ vmw_cursor_plane_atomic_update(struct drm_plane *plane,
 	case VMW_CURSOR_UPDATE_MOB:
 		vmw_cursor_update_mob(dev_priv, vps);
 		break;
+	case VMW_CURSOR_UPDATE_GB_ONLY:
+		bo = vmw_user_object_buffer(&vps->uo);
+		if (bo)
+			vmw_send_define_cursor_cmd(dev_priv, bo->map.virtual,
+						   vps->base.crtc_w,
+						   vps->base.crtc_h,
+						   vps->base.hotspot_x,
+						   vps->base.hotspot_y);
+		break;
 	case VMW_CURSOR_UPDATE_NONE:
 		/* do nothing */
 		break;

drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.h

@@ -33,6 +33,7 @@ static const u32 __maybe_unused vmw_cursor_plane_formats[] = {
 enum vmw_cursor_update_type {
 	VMW_CURSOR_UPDATE_NONE = 0,
 	VMW_CURSOR_UPDATE_LEGACY,
+	VMW_CURSOR_UPDATE_GB_ONLY,
 	VMW_CURSOR_UPDATE_MOB,
 };