drm/i915: Account for scale factor when calculating initial phase

[sfrench/cifs-2.6.git] / drivers / gpu / drm / i915 / intel_display.c

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 9741cc419e1b2bc1f5eb4771ae75468f0099289d..a54843fdeb2f04a353c30af6e86e131c203b2868 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -4850,8 +4850,31 @@ static void cpt_verify_modeset(struct drm_device *dev, int pipe)
  * chroma samples for both of the luma samples, and thus we don't
  * actually get the expected MPEG2 chroma siting convention :(
  * The same behaviour is observed on pre-SKL platforms as well.
+ *
+ * Theory behind the formula (note that we ignore sub-pixel
+ * source coordinates):
+ * s = source sample position
+ * d = destination sample position
+ *
+ * Downscaling 4:1:
+ * -0.5
+ * | 0.0
+ * | |     1.5 (initial phase)
+ * | |     |
+ * v v     v
+ * | s | s | s | s |
+ * |       d       |
+ *
+ * Upscaling 1:4:
+ * -0.5
+ * | -0.375 (initial phase)
+ * | |     0.0
+ * | |     |
+ * v v     v
+ * |       s       |
+ * | d | d | d | d |
  */
-u16 skl_scaler_calc_phase(int sub, bool chroma_cosited)
+u16 skl_scaler_calc_phase(int sub, int scale, bool chroma_cosited)
 {
        int phase = -0x8000;
        u16 trip = 0;
@@ -4859,6 +4882,15 @@ u16 skl_scaler_calc_phase(int sub, bool chroma_cosited)
        if (chroma_cosited)
                phase += (sub - 1) * 0x8000 / sub;
 
+       phase += scale / (2 * sub);
+
+       /*
+        * Hardware initial phase limited to [-0.5:1.5].
+        * Since the max hardware scale factor is 3.0, we
+        * should never actually excdeed 1.0 here.
+        */
+       WARN_ON(phase < -0x8000 || phase > 0x18000);
+
        if (phase < 0)
                phase = 0x10000 + phase;
        else
@@ -5067,13 +5099,20 @@ static void skylake_pfit_enable(struct intel_crtc *crtc)
 
        if (crtc->config->pch_pfit.enabled) {
                u16 uv_rgb_hphase, uv_rgb_vphase;
+               int pfit_w, pfit_h, hscale, vscale;
                int id;
 
                if (WARN_ON(crtc->config->scaler_state.scaler_id < 0))
                        return;
 
-               uv_rgb_hphase = skl_scaler_calc_phase(1, false);
-               uv_rgb_vphase = skl_scaler_calc_phase(1, false);
+               pfit_w = (crtc->config->pch_pfit.size >> 16) & 0xFFFF;
+               pfit_h = crtc->config->pch_pfit.size & 0xFFFF;
+
+               hscale = (crtc->config->pipe_src_w << 16) / pfit_w;
+               vscale = (crtc->config->pipe_src_h << 16) / pfit_h;
+
+               uv_rgb_hphase = skl_scaler_calc_phase(1, hscale, false);
+               uv_rgb_vphase = skl_scaler_calc_phase(1, vscale, false);
 
                id = scaler_state->scaler_id;
                I915_WRITE(SKL_PS_CTRL(pipe, id), PS_SCALER_EN |
@@ -12768,17 +12807,12 @@ static void intel_atomic_commit_tail(struct drm_atomic_state *state)
                        intel_check_cpu_fifo_underruns(dev_priv);
                        intel_check_pch_fifo_underruns(dev_priv);
 
-                       if (!new_crtc_state->active) {
-                               /*
-                                * Make sure we don't call initial_watermarks
-                                * for ILK-style watermark updates.
-                                *
-                                * No clue what this is supposed to achieve.
-                                */
-                               if (INTEL_GEN(dev_priv) >= 9)
-                                       dev_priv->display.initial_watermarks(intel_state,
-                                                                            to_intel_crtc_state(new_crtc_state));
-                       }
+                       /* FIXME unify this for all platforms */
+                       if (!new_crtc_state->active &&
+                           !HAS_GMCH_DISPLAY(dev_priv) &&
+                           dev_priv->display.initial_watermarks)
+                               dev_priv->display.initial_watermarks(intel_state,
+                                                                    to_intel_crtc_state(new_crtc_state));
                }
        }
 
@@ -14646,7 +14680,7 @@ static int intel_framebuffer_init(struct intel_framebuffer *intel_fb,
             fb->height < SKL_MIN_YUV_420_SRC_H ||
             (fb->width % 4) != 0 || (fb->height % 4) != 0)) {
                DRM_DEBUG_KMS("src dimensions not correct for NV12\n");
-               return -EINVAL;
+               goto err;
        }
 
        for (i = 0; i < fb->format->num_planes; i++) {