drm/i915/icl: Enable 2nd DBuf slice only when needed

ICL has two slices of DBuf, each slice of size 1024 blocks.
We should not always enable slice-2. It should be enabled only if
display total required BW is > 12GBps OR more than 1 pipes are enabled.

Changes since V1:
 - typecast total_data_rate to u64 before multiplication to solve any
   possible overflow (Rodrigo)
 - fix where skl_wm_get_hw_state was memsetting ddb, resulting
   enabled_slices to become zero
 - Fix the logic of calculating ddb_size
Changes since V2:
 - If no-crtc is part of commit required_slices will have value "0",
   don't try to disable DBuf slice.
Changes since V3:
 - Create a generic helper to enable/disable slice
 - don't return early if total_data_rate is 0, it may be cursor only
   commit, or atomic modeset without any plane.
Changes since V4:
 - Solve checkpatch warnings
 - use kernel types u8/u64 instead of uint8_t/uint64_t
Changes since V5:
 - Rebase

Signed-off-by: Mahesh Kumar <mahesh1.kumar@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180426142517.16643-3-mahesh1.kumar@intel.com

1 files changed, 10 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 338570e61a1f..84ce66be88f2 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -12258,6 +12258,8 @@ static void skl_update_crtcs(struct drm_atomic_state *state)
 	bool progress;
 	enum pipe pipe;
 	int i;
+	u8 hw_enabled_slices = dev_priv->wm.skl_hw.ddb.enabled_slices;
+	u8 required_slices = intel_state->wm_results.ddb.enabled_slices;
 
 	const struct skl_ddb_entry *entries[I915_MAX_PIPES] = {};
 
@@ -12266,6 +12268,10 @@ static void skl_update_crtcs(struct drm_atomic_state *state)
 		if (new_crtc_state->active)
 			entries[i] = &to_intel_crtc_state(old_crtc_state)->wm.skl.ddb;
 
+	/* If 2nd DBuf slice required, enable it here */
+	if (INTEL_GEN(dev_priv) >= 11 && required_slices > hw_enabled_slices)
+		icl_dbuf_slices_update(dev_priv, required_slices);
+
 	/*
 	 * Whenever the number of active pipes changes, we need to make sure we
 	 * update the pipes in the right order so that their ddb allocations
@@ -12316,6 +12322,10 @@ static void skl_update_crtcs(struct drm_atomic_state *state)
 			progress = true;
 		}
 	} while (progress);
+
+	/* If 2nd DBuf slice is no more required disable it */
+	if (INTEL_GEN(dev_priv) >= 11 && required_slices < hw_enabled_slices)
+		icl_dbuf_slices_update(dev_priv, required_slices);
 }
 
 static void intel_atomic_helper_free_state(struct drm_i915_private *dev_priv)