drm/i915: Use the ilk_disable_lp_wm() return value

ilk_disable_lp_wm() will tell us whether the LP1+ watermarks were
disabled or not, and hence whether we need to for the vblank wait or
not. Let's use that information to eliminate some useless vblank
waits.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1480354637-14209-3-git-send-email-ville.syrjala@linux.intel.com
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index b01faf50fe426f675827c1c7aa1e0c8806ee89ee..1f7d91af60cf483c4087aa4152c019cd79dbbcbe 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5114,10 +5114,8 @@ static void intel_pre_plane_update(struct intel_crtc_state *old_crtc_state)
         *
         * WaCxSRDisabledForSpriteScaling:ivb
         */
-       if (pipe_config->disable_lp_wm) {
-               ilk_disable_lp_wm(dev);
+       if (pipe_config->disable_lp_wm && ilk_disable_lp_wm(dev))
                intel_wait_for_vblank(dev_priv, crtc->pipe);
-       }
 
        /*
         * If we're doing a modeset, we're done.  No need to do any pre-vblank