[Intel-gfx] [PATCH 4/9] drm/i915: Allocate enough DDB for the cursor

[Ville Syrjala]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

Currently we just assume that 32 or 8 blocks of ddb is sufficient
for the cursor. The 32 might be, but the 8 is certainly not. The
minimum we need is at least what level 0 watermarks need, but that
is a bit restrictive, so instead let's calculate what level 7
would need for a 256x256 cursor. We'll use that to determine the
fixed ddb allocation for the cursor. This way the cursor will never
be responsible for missing out on deeper power saving states.

Cc: Neel Desai <neel.desai at intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/intel_pm.c | 33 ++++++++++++++++++++++++++++-----
 1 file changed, 28 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 9e7b4412f7a8..ae9a0ce4dcb9 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3924,12 +3924,35 @@ skl_ddb_get_pipe_allocation_limits(struct drm_i915_private *dev_priv,
 	alloc->end = ddb_size * (width_before_pipe + pipe_width) / total_width;
 }
 
-static unsigned int skl_cursor_allocation(int num_active)
+static int skl_compute_wm_params(const struct intel_crtc_state *crtc_state,
+				 int width, const struct drm_format_info *format,
+				 u64 modifier, unsigned int rotation,
+				 u32 plane_pixel_rate, struct skl_wm_params *wp,
+				 int color_plane);
+static void skl_compute_plane_wm(const struct intel_crtc_state *cstate,
+				 int level,
+				 const struct skl_wm_params *wp,
+				 const struct skl_wm_level *result_prev,
+				 struct skl_wm_level *result /* out */);
+
+static unsigned int
+skl_cursor_allocation(const struct intel_crtc_state *crtc_state,
+		      int num_active)
 {
-	if (num_active == 1)
-		return 32;
+	struct skl_wm_level wm = {};
+	struct skl_wm_params wp;
+	int ret;
+
+	ret = skl_compute_wm_params(crtc_state, 256,
+				    drm_format_info(DRM_FORMAT_ARGB8888),
+				    DRM_FORMAT_MOD_LINEAR,
+				    DRM_MODE_ROTATE_0,
+				    crtc_state->pixel_rate, &wp, 0);
+	WARN_ON(ret);
+
+	skl_compute_plane_wm(crtc_state, 7, &wp, &wm, &wm);
 
-	return 8;
+	return max_t(int, num_active == 1 ? 32 : 8, wm.min_ddb_alloc);
 }
 
 static void skl_ddb_entry_init_from_hw(struct drm_i915_private *dev_priv,
@@ -4354,7 +4377,7 @@ skl_allocate_pipe_ddb(struct intel_crtc_state *cstate,
 		return 0;
 
 	/* Allocate fixed number of blocks for cursor. */
-	total[PLANE_CURSOR] = skl_cursor_allocation(num_active);
+	total[PLANE_CURSOR] = skl_cursor_allocation(cstate, num_active);
 	alloc_size -= total[PLANE_CURSOR];
 	cstate->wm.skl.plane_ddb_y[PLANE_CURSOR].start =
 		alloc->end - total[PLANE_CURSOR];
-- 
2.19.2