drm/armada: add CRTC mode validation

Add CRTC mode validation to reject modes that the CRTC does not support.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

diff --git a/drivers/gpu/drm/armada/armada_crtc.c b/drivers/gpu/drm/armada/armada_crtc.c
index d802a6b..edce74f 100644 (file)
--- a/drivers/gpu/drm/armada/armada_crtc.c
+++ b/drivers/gpu/drm/armada/armada_crtc.c
@@ -168,6 +168,25 @@ static void armada_drm_update_gamma(struct drm_crtc *crtc)
        }
 }
 
+static enum drm_mode_status armada_drm_crtc_mode_valid(struct drm_crtc *crtc,
+       const struct drm_display_mode *mode)
+{
+       if (mode->vscan > 1)
+               return MODE_NO_VSCAN;
+
+       if (mode->flags & DRM_MODE_FLAG_DBLSCAN)
+               return MODE_NO_DBLESCAN;
+
+       if (mode->flags & DRM_MODE_FLAG_HSKEW)
+               return MODE_H_ILLEGAL;
+
+       if (mode->flags & (DRM_MODE_FLAG_BCAST | DRM_MODE_FLAG_PIXMUX |
+                          DRM_MODE_FLAG_CLKDIV2))
+               return MODE_BAD;
+
+       return MODE_OK;
+}
+
 /* The mode_config.mutex will be held for this call */
 static bool armada_drm_crtc_mode_fixup(struct drm_crtc *crtc,
        const struct drm_display_mode *mode, struct drm_display_mode *adj)
@@ -499,6 +518,7 @@ static void armada_drm_crtc_atomic_enable(struct drm_crtc *crtc,
 }
 
 static const struct drm_crtc_helper_funcs armada_crtc_helper_funcs = {
+       .mode_valid     = armada_drm_crtc_mode_valid,
        .mode_fixup     = armada_drm_crtc_mode_fixup,
        .mode_set_nofb  = armada_drm_crtc_mode_set_nofb,
        .atomic_check   = armada_drm_crtc_atomic_check,