drm/i915: Add missing NULL check before calling initial_watermarks

Not all platforms set this callback, so NULL check it before calling it.

v2:
- Call intel_update_watermarks() on HSW+ where the callback is not set.
  (Matt)

CC: Matt Roper <matthew.d.roper@intel.com>
Fixes: commit ed4a6a7ca853 ("drm/i915: Add two-stage ILK-style watermark programming (v11)")
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1456776633-3401-1-git-send-email-imre.deak@intel.com
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index c803690293d7..368d24728b16 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -4957,7 +4957,8 @@ static void ironlake_crtc_enable(struct drm_crtc *crtc)
          */
         intel_crtc_load_lut(crtc);
 
-        dev_priv->display.initial_watermarks(intel_crtc->config);
+        if (dev_priv->display.initial_watermarks != NULL)
+                dev_priv->display.initial_watermarks(intel_crtc->config);
         intel_enable_pipe(intel_crtc);
 
         if (intel_crtc->config->has_pch_encoder)
@@ -5056,7 +5057,10 @@ static void haswell_crtc_enable(struct drm_crtc *crtc)
         if (!intel_crtc->config->has_dsi_encoder)
                 intel_ddi_enable_transcoder_func(crtc);
 
-        dev_priv->display.initial_watermarks(pipe_config);
+        if (dev_priv->display.initial_watermarks != NULL)
+                dev_priv->display.initial_watermarks(pipe_config);
+        else
+                intel_update_watermarks(crtc);
         intel_enable_pipe(intel_crtc);
 
         if (intel_crtc->config->has_pch_encoder)