drm/qxl: reapply cursor after resetting primary

QXL associates mouse state with its primary plane.

Destroying a primary plane and putting a new one in place has the side
effect of destroying the cursor as well.

This commit changes the driver to reapply the cursor any time a new
primary is created. It achieves this by keeping a reference to the
cursor bo on the qxl_crtc struct.

This fix is very similar to

commit 4532b241 ("drm/qxl: reapply cursor after SetCrtc calls")

which got implicitly reverted as part of implementing the atomic
modeset feature.

Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Dave Airlie <airlied@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1512097
Fixes: 1277eed5 ("drm: qxl: Atomic phase 1: convert cursor to universal plane")
Cc: stable@vger.kernel.org
Signed-off-by: Ray Strode <rstrode@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/qxl/qxl_display.c

@@ -289,6 +289,7 @@ static void qxl_crtc_destroy(struct drm_crtc *crtc)
 {
 	struct qxl_crtc *qxl_crtc = to_qxl_crtc(crtc);
 
+	qxl_bo_unref(&qxl_crtc->cursor_bo);
 	drm_crtc_cleanup(crtc);
 	kfree(qxl_crtc);
 }
@@ -495,6 +496,53 @@ static int qxl_primary_atomic_check(struct drm_plane *plane,
 	return 0;
 }
 
+static int qxl_primary_apply_cursor(struct drm_plane *plane)
+{
+	struct drm_device *dev = plane->dev;
+	struct qxl_device *qdev = dev->dev_private;
+	struct drm_framebuffer *fb = plane->state->fb;
+	struct qxl_crtc *qcrtc = to_qxl_crtc(plane->state->crtc);
+	struct qxl_cursor_cmd *cmd;
+	struct qxl_release *release;
+	int ret = 0;
+
+	if (!qcrtc->cursor_bo)
+		return 0;
+
+	ret = qxl_alloc_release_reserved(qdev, sizeof(*cmd),
+					 QXL_RELEASE_CURSOR_CMD,
+					 &release, NULL);
+	if (ret)
+		return ret;
+
+	ret = qxl_release_list_add(release, qcrtc->cursor_bo);
+	if (ret)
+		goto out_free_release;
+
+	ret = qxl_release_reserve_list(release, false);
+	if (ret)
+		goto out_free_release;
+
+	cmd = (struct qxl_cursor_cmd *)qxl_release_map(qdev, release);
+	cmd->type = QXL_CURSOR_SET;
+	cmd->u.set.position.x = plane->state->crtc_x + fb->hot_x;
+	cmd->u.set.position.y = plane->state->crtc_y + fb->hot_y;
+
+	cmd->u.set.shape = qxl_bo_physical_address(qdev, qcrtc->cursor_bo, 0);
+
+	cmd->u.set.visible = 1;
+	qxl_release_unmap(qdev, release, &cmd->release_info);
+
+	qxl_push_cursor_ring_release(qdev, release, QXL_CMD_CURSOR, false);
+	qxl_release_fence_buffer_objects(release);
+
+	return ret;
+
+out_free_release:
+	qxl_release_free(qdev, release);
+	return ret;
+}
+
 static void qxl_primary_atomic_update(struct drm_plane *plane,
 				      struct drm_plane_state *old_state)
 {
@@ -510,6 +558,7 @@ static void qxl_primary_atomic_update(struct drm_plane *plane,
 	    .x2 = qfb->base.width,
 	    .y2 = qfb->base.height
 	};
+	int ret;
 	bool same_shadow = false;
 
 	if (old_state->fb) {
@@ -531,6 +580,11 @@ static void qxl_primary_atomic_update(struct drm_plane *plane,
 		if (!same_shadow)
 			qxl_io_destroy_primary(qdev);
 		bo_old->is_primary = false;
+
+		ret = qxl_primary_apply_cursor(plane);
+		if (ret)
+			DRM_ERROR(
+			"could not set cursor after creating primary");
 	}
 
 	if (!bo->is_primary) {
@@ -571,6 +625,7 @@ static void qxl_cursor_atomic_update(struct drm_plane *plane,
 	struct drm_device *dev = plane->dev;
 	struct qxl_device *qdev = dev->dev_private;
 	struct drm_framebuffer *fb = plane->state->fb;
+	struct qxl_crtc *qcrtc = to_qxl_crtc(plane->state->crtc);
 	struct qxl_release *release;
 	struct qxl_cursor_cmd *cmd;
 	struct qxl_cursor *cursor;
@@ -628,6 +683,10 @@ static void qxl_cursor_atomic_update(struct drm_plane *plane,
 		cmd->u.set.shape = qxl_bo_physical_address(qdev,
 							   cursor_bo, 0);
 		cmd->type = QXL_CURSOR_SET;
+
+		qxl_bo_unref(&qcrtc->cursor_bo);
+		qcrtc->cursor_bo = cursor_bo;
+		cursor_bo = NULL;
 	} else {
 
 		ret = qxl_release_reserve_list(release, true);

drivers/gpu/drm/qxl/qxl_drv.h

@@ -111,6 +111,8 @@ struct qxl_bo_list {
 struct qxl_crtc {
 	struct drm_crtc base;
 	int index;
+
+	struct qxl_bo *cursor_bo;
 };
 
 struct qxl_output {