drm/i915: Reject odd pipe source width with double wide/dual link

In order to guarantee that pipe_src_w/h matches the user mode h/vdisplay
we must not adjust pipe_src_w to accommodate double wide/dual link.
Instead just reject the mode outright.

This will allows us to rely on crtc_state->mode for plane clipping.

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171123190502.28449-2-ville.syrjala@linux.intel.com
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/drm/i915/intel_display.c

@@ -6372,9 +6372,18 @@ static int intel_crtc_compute_config(struct intel_crtc *crtc,
 	 * - LVDS dual channel mode
 	 * - Double wide pipe
 	 */
-	if ((intel_crtc_has_type(pipe_config, INTEL_OUTPUT_LVDS) &&
-	     intel_is_dual_link_lvds(dev)) || pipe_config->double_wide)
-		pipe_config->pipe_src_w &= ~1;
+	if (pipe_config->pipe_src_w & 1) {
+		if (pipe_config->double_wide) {
+			DRM_DEBUG_KMS("Odd pipe source width not supported with double wide pipe\n");
+			return -EINVAL;
+		}
+
+		if (intel_crtc_has_type(pipe_config, INTEL_OUTPUT_LVDS) &&
+		    intel_is_dual_link_lvds(dev)) {
+			DRM_DEBUG_KMS("Odd pipe source width not supported with dual link LVDS\n");
+			return -EINVAL;
+		}
+	}
 
 	/* Cantiga+ cannot handle modes with a hsync front porch of 0.
 	 * WaPruneModeWithIncorrectHsyncOffset:ctg,elk,ilk,snb,ivb,vlv,hsw.