Merge tag 'drm-intel-fixes-2015-05-21' of git://anongit.freedesktop.org/drm-intel into drm-fixes

There's a stable backport from Ander [1] that combines this and a few
other commits to fix the flickering on v4.0, reported in [2] among
others. Having this upstream is obviously a requirement for stable.

* tag 'drm-intel-fixes-2015-05-21' of git://anongit.freedesktop.org/drm-intel:
  drm/i915: fix screen flickering

1 files changed, 11 insertions, 13 deletions

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index fa4ccb346389..555b896d2bda 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -2045,22 +2045,20 @@ static void ilk_compute_wm_parameters(struct drm_crtc *crtc,
         p->pipe_htotal = intel_crtc->config->base.adjusted_mode.crtc_htotal;
         p->pixel_rate = ilk_pipe_pixel_rate(dev, crtc);
 
-        if (crtc->primary->state->fb) {
-                p->pri.enabled = true;
+        if (crtc->primary->state->fb)
                 p->pri.bytes_per_pixel =
                         crtc->primary->state->fb->bits_per_pixel / 8;
-        } else {
-                p->pri.enabled = false;
-                p->pri.bytes_per_pixel = 0;
-        }
+        else
+                p->pri.bytes_per_pixel = 4;
+
+        p->cur.bytes_per_pixel = 4;
+        /*
+         * TODO: for now, assume primary and cursor planes are always enabled.
+         * Setting them to false makes the screen flicker.
+         */
+        p->pri.enabled = true;
+        p->cur.enabled = true;
 
-        if (crtc->cursor->state->fb) {
-                p->cur.enabled = true;
-                p->cur.bytes_per_pixel = 4;
-        } else {
-                p->cur.enabled = false;
-                p->cur.bytes_per_pixel = 0;
-        }
         p->pri.horiz_pixels = intel_crtc->config->pipe_src_w;
         p->cur.horiz_pixels = intel_crtc->base.cursor->state->crtc_w;