drm/vc4: Allocate the right amount of space for boot-time CRTC state.

Without this, the first modeset would dereference past the allocation
when trying to free the mm node.

Signed-off-by: Eric Anholt <eric@anholt.net>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170328201343.4884-1-eric@anholt.net
Fixes: d8dbf44f13b9 ("drm/vc4: Make the CRTCs cooperate on allocating display lists.")
Cc: <stable@vger.kernel.org> # v4.6+
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 12 insertions, 1 deletions

diff --git a/drivers/gpu/drm/vc4/vc4_crtc.c b/drivers/gpu/drm/vc4/vc4_crtc.c
index 0c06844af445..9fcf05ca492b 100644
--- a/drivers/gpu/drm/vc4/vc4_crtc.c
+++ b/drivers/gpu/drm/vc4/vc4_crtc.c
@@ -846,6 +846,17 @@ static void vc4_crtc_destroy_state(struct drm_crtc *crtc,
         drm_atomic_helper_crtc_destroy_state(crtc, state);
 }
 
+static void
+vc4_crtc_reset(struct drm_crtc *crtc)
+{
+        if (crtc->state)
+                __drm_atomic_helper_crtc_destroy_state(crtc->state);
+
+        crtc->state = kzalloc(sizeof(struct vc4_crtc_state), GFP_KERNEL);
+        if (crtc->state)
+                crtc->state->crtc = crtc;
+}
+
 static const struct drm_crtc_funcs vc4_crtc_funcs = {
         .set_config = drm_atomic_helper_set_config,
         .destroy = vc4_crtc_destroy,
@@ -853,7 +864,7 @@ static const struct drm_crtc_funcs vc4_crtc_funcs = {
         .set_property = NULL,
         .cursor_set = NULL, /* handled by drm_mode_cursor_universal */
         .cursor_move = NULL, /* handled by drm_mode_cursor_universal */
-        .reset = drm_atomic_helper_crtc_reset,
+        .reset = vc4_crtc_reset,
         .atomic_duplicate_state = vc4_crtc_duplicate_state,
         .atomic_destroy_state = vc4_crtc_destroy_state,
         .gamma_set = vc4_crtc_gamma_set,