1 files changed, 95 insertions, 30 deletions

diff --git a/drivers/gpu/drm/drm_plane_helper.c b/drivers/gpu/drm/drm_plane_helper.c
index 37b9333cee49..6d133149cc74 100644
--- a/drivers/gpu/drm/drm_plane_helper.c
+++ b/drivers/gpu/drm/drm_plane_helper.c
@@ -25,6 +25,7 @@
 
 #include <linux/list.h>
 #include <drm/drmP.h>
+#include <drm/drm_plane_helper.h>
 #include <drm/drm_rect.h>
 #include <drm/drm_plane_helper.h>
 
@@ -74,6 +75,79 @@ static int get_connectors_for_crtc(struct drm_crtc *crtc,
 }
 
 /**
+ * drm_plane_helper_check_update() - Check plane update for validity
+ * @plane: plane object to update
+ * @crtc: owning CRTC of owning plane
+ * @fb: framebuffer to flip onto plane
+ * @src: source coordinates in 16.16 fixed point
+ * @dest: integer destination coordinates
+ * @clip: integer clipping coordinates
+ * @min_scale: minimum @src:@dest scaling factor in 16.16 fixed point
+ * @max_scale: maximum @src:@dest scaling factor in 16.16 fixed point
+ * @can_position: is it legal to position the plane such that it
+ *                doesn't cover the entire crtc?  This will generally
+ *                only be false for primary planes.
+ * @can_update_disabled: can the plane be updated while the crtc
+ *                       is disabled?
+ * @visible: output parameter indicating whether plane is still visible after
+ *           clipping
+ *
+ * Checks that a desired plane update is valid.  Drivers that provide
+ * their own plane handling rather than helper-provided implementations may
+ * still wish to call this function to avoid duplication of error checking
+ * code.
+ *
+ * RETURNS:
+ * Zero if update appears valid, error code on failure
+ */
+int drm_plane_helper_check_update(struct drm_plane *plane,
+                                    struct drm_crtc *crtc,
+                                    struct drm_framebuffer *fb,
+                                    struct drm_rect *src,
+                                    struct drm_rect *dest,
+                                    const struct drm_rect *clip,
+                                    int min_scale,
+                                    int max_scale,
+                                    bool can_position,
+                                    bool can_update_disabled,
+                                    bool *visible)
+{
+        int hscale, vscale;
+
+        if (!crtc->enabled && !can_update_disabled) {
+                DRM_DEBUG_KMS("Cannot update plane of a disabled CRTC.\n");
+                return -EINVAL;
+        }
+
+        /* Check scaling */
+        hscale = drm_rect_calc_hscale(src, dest, min_scale, max_scale);
+        vscale = drm_rect_calc_vscale(src, dest, min_scale, max_scale);
+        if (hscale < 0 || vscale < 0) {
+                DRM_DEBUG_KMS("Invalid scaling of plane\n");
+                return -ERANGE;
+        }
+
+        *visible = drm_rect_clip_scaled(src, dest, clip, hscale, vscale);
+        if (!*visible)
+                /*
+                 * Plane isn't visible; some drivers can handle this
+                 * so we just return success here.  Drivers that can't
+                 * (including those that use the primary plane helper's
+                 * update function) will return an error from their
+                 * update_plane handler.
+                 */
+                return 0;
+
+        if (!can_position && !drm_rect_equals(dest, clip)) {
+                DRM_DEBUG_KMS("Plane must cover entire CRTC\n");
+                return -EINVAL;
+        }
+
+        return 0;
+}
+EXPORT_SYMBOL(drm_plane_helper_check_update);
+
+/**
  * drm_primary_helper_update() - Helper for primary plane update
  * @plane: plane object to update
  * @crtc: owning CRTC of owning plane
@@ -121,51 +195,42 @@ int drm_primary_helper_update(struct drm_plane *plane, struct drm_crtc *crtc,
                 .x = src_x >> 16,
                 .y = src_y >> 16,
         };
+        struct drm_rect src = {
+                .x1 = src_x,
+                .y1 = src_y,
+                .x2 = src_x + src_w,
+                .y2 = src_y + src_h,
+        };
         struct drm_rect dest = {
                 .x1 = crtc_x,
                 .y1 = crtc_y,
                 .x2 = crtc_x + crtc_w,
                 .y2 = crtc_y + crtc_h,
         };
-        struct drm_rect clip = {
+        const struct drm_rect clip = {
                 .x2 = crtc->mode.hdisplay,
                 .y2 = crtc->mode.vdisplay,
         };
         struct drm_connector **connector_list;
         int num_connectors, ret;
+        bool visible;
 
-        if (!crtc->enabled) {
-                DRM_DEBUG_KMS("Cannot update primary plane of a disabled CRTC.\n");
-                return -EINVAL;
-        }
-
-        /* Disallow subpixel positioning */
-        if ((src_x | src_y | src_w | src_h) & SUBPIXEL_MASK) {
-                DRM_DEBUG_KMS("Primary plane does not support subpixel positioning\n");
-                return -EINVAL;
-        }
-
-        /* Disallow scaling */
-        src_w >>= 16;
-        src_h >>= 16;
-        if (crtc_w != src_w || crtc_h != src_h) {
-                DRM_DEBUG_KMS("Can't scale primary plane\n");
-                return -EINVAL;
-        }
-
-        /* Make sure primary plane covers entire CRTC */
-        drm_rect_intersect(&dest, &clip);
-        if (dest.x1 != 0 || dest.y1 != 0 ||
-            dest.x2 != crtc->mode.hdisplay || dest.y2 != crtc->mode.vdisplay) {
-                DRM_DEBUG_KMS("Primary plane must cover entire CRTC\n");
-                return -EINVAL;
-        }
-
-        /* Framebuffer must be big enough to cover entire plane */
-        ret = drm_crtc_check_viewport(crtc, crtc_x, crtc_y, &crtc->mode, fb);
+        ret = drm_plane_helper_check_update(plane, crtc, fb,
+                                            &src, &dest, &clip,
+                                            DRM_PLANE_HELPER_NO_SCALING,
+                                            DRM_PLANE_HELPER_NO_SCALING,
+                                            false, false, &visible);
         if (ret)
                 return ret;
 
+        if (!visible)
+                /*
+                 * Primary plane isn't visible.  Note that unless a driver
+                 * provides their own disable function, this will just
+                 * wind up returning -EINVAL to userspace.
+                 */
+                return plane->funcs->disable_plane(plane);
+
         /* Find current connectors for CRTC */
         num_connectors = get_connectors_for_crtc(crtc, NULL, 0);
         BUG_ON(num_connectors == 0);