[PATCH 1/4] drm: Check CRTC compatibility in setplane

Matt Roper
2014-04-30T17:07:00Z

The DRM core setplane code should check that the plane is usable on the
specified CRTC before calling into the driver.

Prior to this patch, a plane's possible_crtcs field was purely
informational for userspace and was never actually verified at the
kernel level (aside from the primary plane helper).

Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
---
drivers/gpu/drm/drm_crtc.c | 7 +++++++
drivers/gpu/drm/drm_plane_helper.c | 6 ------
2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 461d19b..b6d6c04 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -2140,6 +2140,13 @@ int drm_mode_setplane(struct drm_device *dev, void *data,
}
crtc = obj_to_crtc(obj);

+ /* Check whether this plane is usable on this CRTC */
+ if (!(plane->possible_crtcs & drm_crtc_mask(crtc))) {
+ DRM_DEBUG_KMS("Invalid crtc for plane\n");
+ ret = -EINVAL;
+ goto out;
+ }
+
fb = drm_framebuffer_lookup(dev, plane_req->fb_id);
if (!fb) {
DRM_DEBUG_KMS("Unknown framebuffer ID %d\n",
diff --git a/drivers/gpu/drm/drm_plane_helper.c b/drivers/gpu/drm/drm_plane_helper.c
index d966afa..b601233 100644
--- a/drivers/gpu/drm/drm_plane_helper.c
+++ b/drivers/gpu/drm/drm_plane_helper.c
@@ -137,12 +137,6 @@ int drm_primary_helper_update(struct drm_plane *plane, struct drm_crtc *crtc,
return -EINVAL;
}

- /* Primary planes are locked to their owning CRTC */
- if (plane->possible_crtcs != drm_crtc_mask(crtc)) {
- DRM_DEBUG_KMS("Cannot change primary plane CRTC\n");
- return -EINVAL;
- }
-
/* Disallow scaling */
src_w >>= 16;
src_h >>= 16;
--
1.8.5.1