[PATCH] drm: move check for min/max width/height for atomic drivers

[Rob Clark]

drm-hwc + android tries to create an fb for the wallpaper layer, which
is larger than the screen resolution, and potentially larger than
mode_config->max_{width,height}.  But the plane src_w/src_h is within
the max limits, so it is something the hardware can otherwise do.

For atomic drivers, defer the check to drm_atomic_plane_check().

Signed-off-by: Rob Clark <robdclark at gmail.com>
---
 drivers/gpu/drm/drm_atomic.c | 17 +++++++++++++++++
 drivers/gpu/drm/drm_crtc.c   | 26 +++++++++++++++++---------
 2 files changed, 34 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 34edd4f..fb0f07ce 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -846,7 +846,9 @@ plane_switching_crtc(struct drm_atomic_state *state,
 static int drm_atomic_plane_check(struct drm_plane *plane,
 		struct drm_plane_state *state)
 {
+	struct drm_mode_config *config = &plane->dev->mode_config;
 	unsigned int fb_width, fb_height;
+	unsigned int min_width, max_width, min_height, max_height;
 	int ret;
 
 	/* either *both* CRTC and FB must be set, or neither */
@@ -909,6 +911,21 @@ static int drm_atomic_plane_check(struct drm_plane *plane,
 		return -ENOSPC;
 	}
 
+	min_width = config->min_width << 16;
+	max_width = config->max_width << 16;
+	min_height = config->min_height << 16;
+	max_height = config->max_height << 16;
+
+	/* Make sure source dimensions are within bounds. */
+	if (min_width > state->src_w || state->src_w > max_width ||
+	    min_height > state->src_h || state->src_h > max_height) {
+		DRM_DEBUG_ATOMIC("Invalid source size "
+				 "%u.%06ux%u.%06u\n",
+				 state->src_w >> 16, ((state->src_w & 0xffff) * 15625) >> 10,
+				 state->src_h >> 16, ((state->src_h & 0xffff) * 15625) >> 10);
+		return -ERANGE;
+	}
+
 	if (plane_switching_crtc(state->state, plane, state)) {
 		DRM_DEBUG_ATOMIC("[PLANE:%d:%s] switching CRTC directly\n",
 				 plane->base.id, plane->name);
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index b4b973f..7294bde 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -3369,15 +3369,23 @@ internal_framebuffer_create(struct drm_device *dev,
 		return ERR_PTR(-EINVAL);
 	}
 
-	if ((config->min_width > r->width) || (r->width > config->max_width)) {
-		DRM_DEBUG_KMS("bad framebuffer width %d, should be >= %d && <= %d\n",
-			  r->width, config->min_width, config->max_width);
-		return ERR_PTR(-EINVAL);
-	}
-	if ((config->min_height > r->height) || (r->height > config->max_height)) {
-		DRM_DEBUG_KMS("bad framebuffer height %d, should be >= %d && <= %d\n",
-			  r->height, config->min_height, config->max_height);
-		return ERR_PTR(-EINVAL);
+	/* for atomic drivers, we check the src dimensions in
+	 * drm_atomic_plane_check().. allow creation of a fb
+	 * that is larger than what can be scanned out, as
+	 * long as userspace doesn't try to scanout a portion
+	 * of the fb that is too large.
+	 */
+	if (!file_priv->atomic) {
+		if ((config->min_width > r->width) || (r->width > config->max_width)) {
+			DRM_DEBUG_KMS("bad framebuffer width %d, should be >= %d && <= %d\n",
+				  r->width, config->min_width, config->max_width);
+			return ERR_PTR(-EINVAL);
+		}
+		if ((config->min_height > r->height) || (r->height > config->max_height)) {
+			DRM_DEBUG_KMS("bad framebuffer height %d, should be >= %d && <= %d\n",
+				  r->height, config->min_height, config->max_height);
+			return ERR_PTR(-EINVAL);
+		}
 	}
 
 	if (r->flags & DRM_MODE_FB_MODIFIERS &&
-- 
2.7.4