drm/i915: Provide a device level .mode_valid() hook

We never support certain mode flags etc. Reject those early on in the
mode_config.mode_valid() hook. That allows us to remove some duplicated
checks from the connector .mode_valid() hooks, and it guarantees that
we never see those flags even from user mode as the
mode_config.mode_valid() hooks gets executed for those as well.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171114183258.16976-11-ville.syrjala@linux.intel.com
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_crt.c

@@ -304,9 +304,6 @@ intel_crt_mode_valid(struct drm_connector *connector,
 	int max_dotclk = dev_priv->max_dotclk_freq;
 	int max_clock;
 
-	if (mode->flags & DRM_MODE_FLAG_DBLSCAN)
-		return MODE_NO_DBLESCAN;
-
 	if (mode->clock < 25000)
 		return MODE_CLOCK_LOW;
 

drivers/gpu/drm/i915/intel_display.c

@@ -14082,10 +14082,37 @@ static void intel_atomic_state_free(struct drm_atomic_state *state)
 	kfree(state);
 }
 
+static enum drm_mode_status
+intel_mode_valid(struct drm_device *dev,
+		 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_CSYNC |
+			   DRM_MODE_FLAG_NCSYNC |
+			   DRM_MODE_FLAG_PCSYNC))
+		return MODE_HSYNC;
+
+	if (mode->flags & (DRM_MODE_FLAG_BCAST |
+			   DRM_MODE_FLAG_PIXMUX |
+			   DRM_MODE_FLAG_CLKDIV2))
+		return MODE_BAD;
+
+	return MODE_OK;
+}
+
 static const struct drm_mode_config_funcs intel_mode_funcs = {
 	.fb_create = intel_user_framebuffer_create,
 	.get_format_info = intel_get_format_info,
 	.output_poll_changed = intel_fbdev_output_poll_changed,
+	.mode_valid = intel_mode_valid,
 	.atomic_check = intel_atomic_check,
 	.atomic_commit = intel_atomic_commit,
 	.atomic_state_alloc = intel_atomic_state_alloc,

drivers/gpu/drm/i915/intel_dsi.c

@@ -1266,11 +1266,6 @@ intel_dsi_mode_valid(struct drm_connector *connector,
 
 	DRM_DEBUG_KMS("\n");
 
-	if (mode->flags & DRM_MODE_FLAG_DBLSCAN) {
-		DRM_DEBUG_KMS("MODE_NO_DBLESCAN\n");
-		return MODE_NO_DBLESCAN;
-	}
-
 	if (fixed_mode) {
 		if (mode->hdisplay > fixed_mode->hdisplay)
 			return MODE_PANEL;

drivers/gpu/drm/i915/intel_dvo.c

@@ -219,9 +219,6 @@ intel_dvo_mode_valid(struct drm_connector *connector,
 	int max_dotclk = to_i915(connector->dev)->max_dotclk_freq;
 	int target_clock = mode->clock;
 
-	if (mode->flags & DRM_MODE_FLAG_DBLSCAN)
-		return MODE_NO_DBLESCAN;
-
 	/* XXX: Validate clock range */
 
 	if (fixed_mode) {

drivers/gpu/drm/i915/intel_fbc.c

@@ -794,8 +794,7 @@ static bool intel_fbc_can_activate(struct intel_crtc *crtc)
 		return false;
 	}
 
-	if ((cache->crtc.mode_flags & DRM_MODE_FLAG_INTERLACE) ||
-	    (cache->crtc.mode_flags & DRM_MODE_FLAG_DBLSCAN)) {
+	if (cache->crtc.mode_flags & DRM_MODE_FLAG_INTERLACE) {
 		fbc->no_fbc_reason = "incompatible mode";
 		return false;
 	}

drivers/gpu/drm/i915/intel_hdmi.c

@@ -1314,9 +1314,6 @@ intel_hdmi_mode_valid(struct drm_connector *connector,
 	bool force_dvi =
 		READ_ONCE(to_intel_digital_connector_state(connector->state)->force_audio) == HDMI_AUDIO_OFF_DVI;
 
-	if (mode->flags & DRM_MODE_FLAG_DBLSCAN)
-		return MODE_NO_DBLESCAN;
-
 	clock = mode->clock;
 
 	if ((mode->flags & DRM_MODE_FLAG_3D_MASK) == DRM_MODE_FLAG_3D_FRAME_PACKING)

drivers/gpu/drm/i915/intel_sdvo.c

@@ -1607,9 +1607,6 @@ intel_sdvo_mode_valid(struct drm_connector *connector,
 	struct intel_sdvo *intel_sdvo = intel_attached_sdvo(connector);
 	int max_dotclk = to_i915(connector->dev)->max_dotclk_freq;
 
-	if (mode->flags & DRM_MODE_FLAG_DBLSCAN)
-		return MODE_NO_DBLESCAN;
-
 	if (intel_sdvo->pixel_clock_min > mode->clock)
 		return MODE_CLOCK_LOW;