drm/arm/hdlcd: Reject atomic commits that disable only the plane

The HDLCD engine needs an active plane while the CRTC is active, as
it will start scanning out data from HDLCD_REG_FB_BASE once it gets
enabled. Make sure that the only available plane doesn't get disabled
while the CRTC remains active, as this will scanout invalid data.

Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>

2 files changed, 19 insertions, 17 deletions

diff --git a/drivers/gpu/drm/arm/hdlcd_crtc.c b/drivers/gpu/drm/arm/hdlcd_crtc.c
index 8978d82159e5..e4d67b70244d 100644
--- a/drivers/gpu/drm/arm/hdlcd_crtc.c
+++ b/drivers/gpu/drm/arm/hdlcd_crtc.c
@@ -229,6 +229,8 @@ static const struct drm_crtc_helper_funcs hdlcd_crtc_helper_funcs = {
 static int hdlcd_plane_atomic_check(struct drm_plane *plane,
                                     struct drm_plane_state *state)
 {
+        int i;
+        struct drm_crtc *crtc;
         struct drm_crtc_state *crtc_state;
         u32 src_h = state->src_h >> 16;
 
@@ -238,20 +240,17 @@ static int hdlcd_plane_atomic_check(struct drm_plane *plane,
                 return -EINVAL;
         }
 
-        if (!state->fb || !state->crtc)
-                return 0;
-
-        crtc_state = drm_atomic_get_existing_crtc_state(state->state,
-                                                        state->crtc);
-        if (!crtc_state) {
-                DRM_DEBUG_KMS("Invalid crtc state\n");
-                return -EINVAL;
+        for_each_new_crtc_in_state(state->state, crtc, crtc_state, i) {
+                /* we cannot disable the plane while the CRTC is active */
+                if (!state->fb && crtc_state->active)
+                        return -EINVAL;
+                return drm_atomic_helper_check_plane_state(state, crtc_state,
+                                                DRM_PLANE_HELPER_NO_SCALING,
+                                                DRM_PLANE_HELPER_NO_SCALING,
+                                                false, true);
         }
 
-        return drm_atomic_helper_check_plane_state(state, crtc_state,
-                                                   DRM_PLANE_HELPER_NO_SCALING,
-                                                   DRM_PLANE_HELPER_NO_SCALING,
-                                                   false, true);
+        return 0;
 }
 
 static void hdlcd_plane_atomic_update(struct drm_plane *plane,
diff --git a/drivers/gpu/drm/arm/hdlcd_drv.c b/drivers/gpu/drm/arm/hdlcd_drv.c
index 70fca288313a..0ed1cde98cf8 100644
--- a/drivers/gpu/drm/arm/hdlcd_drv.c
+++ b/drivers/gpu/drm/arm/hdlcd_drv.c
@@ -325,6 +325,7 @@ err_fbdev:
 err_vblank:
         pm_runtime_disable(drm->dev);
 err_pm_active:
+        drm_atomic_helper_shutdown(drm);
         component_unbind_all(dev, drm);
 err_unload:
         of_node_put(hdlcd->crtc.port);
@@ -350,16 +351,18 @@ static void hdlcd_drm_unbind(struct device *dev)
         component_unbind_all(dev, drm);
         of_node_put(hdlcd->crtc.port);
         hdlcd->crtc.port = NULL;
-        pm_runtime_get_sync(drm->dev);
+        pm_runtime_get_sync(dev);
+        drm_crtc_vblank_off(&hdlcd->crtc);
         drm_irq_uninstall(drm);
-        pm_runtime_put_sync(drm->dev);
-        pm_runtime_disable(drm->dev);
-        of_reserved_mem_device_release(drm->dev);
         drm_atomic_helper_shutdown(drm);
+        pm_runtime_put(dev);
+        if (pm_runtime_enabled(dev))
+                pm_runtime_disable(dev);
+        of_reserved_mem_device_release(dev);
         drm_mode_config_cleanup(drm);
-        drm_dev_put(drm);
         drm->dev_private = NULL;
         dev_set_drvdata(dev, NULL);
+        drm_dev_put(drm);
 }
 
 static const struct component_master_ops hdlcd_master_ops = {