[Intel-gfx] [PATCH 1/2] drm/i915: Calculate ironlake intermediate watermarks correctly

[Maarten Lankhorst]

The watermarks it should calculate against are the old optimal watermarks.
The currently active crtc watermarks are pure fiction, and are invalid in
case of a nonblocking modeset, page flip enabling/disabling planes or any
other reason.

When the crtc is disabled or during a modeset the intermediate watermarks
don't need to be programmed separately, and could be directly assigned
to the optimal watermarks.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/intel_pm.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index cacb65fa2dd5..7da701dc3caa 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -2639,7 +2639,9 @@ static int ilk_compute_intermediate_wm(struct drm_device *dev,
 				       struct intel_crtc_state *newstate)
 {
 	struct intel_pipe_wm *a = &newstate->wm.ilk.intermediate;
-	struct intel_pipe_wm *b = &intel_crtc->wm.active.ilk;
+	const struct drm_crtc_state *old_drm_state =
+		drm_atomic_get_old_crtc_state(newstate->base.state, &intel_crtc->base);
+	const struct intel_pipe_wm *b = &to_intel_crtc_state(old_drm_state)->wm.ilk.optimal;
 	int level, max_level = ilk_wm_max_level(to_i915(dev));
 
 	/*
@@ -2648,6 +2650,9 @@ static int ilk_compute_intermediate_wm(struct drm_device *dev,
 	 * and after the vblank.
 	 */
 	*a = newstate->wm.ilk.optimal;
+	if (!newstate->base.active || drm_atomic_crtc_needs_modeset(&newstate->base))
+		return 0;
+
 	a->pipe_enabled |= b->pipe_enabled;
 	a->sprites_enabled |= b->sprites_enabled;
 	a->sprites_scaled |= b->sprites_scaled;
-- 
2.7.4