drm/i915/skl: Update watermarks before the crtc is disabled.

On skylake some of the registers are only writable when the correct
power wells are enabled. Because of this watermarks have to be updated
before the crtc turns off, or you get unclaimed register read and write
warnings.

This patch needs to be modified slightly to apply to -fixes.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92181
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: stable@vger.kernel.org
Cc: Matt Roper <matthew.d.roper@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1447945645-32005-4-git-send-email-maarten.lankhorst@linux.intel.com
Reviewed-by: Ander Conselvan de Oliveira <conselvan2@gmail.com>

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index a8fb7cf0b3e1e7caf36b733441843b0b971aa215..f118f7ec43680db61bb6858d1c7821b913a4a981 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -4804,7 +4804,7 @@ static void intel_post_plane_update(struct intel_crtc *crtc)
 
        crtc->wm.cxsr_allowed = true;
 
-       if (pipe_config->wm_changed)
+       if (pipe_config->wm_changed && pipe_config->base.active)
                intel_update_watermarks(&crtc->base);
 
        if (atomic->update_fbc)
@@ -13421,6 +13421,9 @@ static int intel_atomic_commit(struct drm_device *dev,
                         */
                        intel_check_cpu_fifo_underruns(dev_priv);
                        intel_check_pch_fifo_underruns(dev_priv);
+
+                       if (!crtc->state->active)
+                               intel_update_watermarks(crtc);
                }
        }