drm/i915: Try to make bigjoiner work in atomic check

 When the clock is higher than the dotclock, try with 2 pipes enabled.
 If we can enable 2, then we will go into big joiner mode, and steal
 the adjacent crtc.

 This only links the crtc's in software, no hardware or plane
 programming is done yet. Blobs are also copied from the master's
 crtc_state, so it doesn't depend at commit time on the other
 crtc_state.

v6:
* Enable dSC for any mode->hdisplay > 5120
v5:
* Remove intel_dp_max_dotclock (Manasi)
v4:
* Fixes in intel_crtc_compute_config (Ville)
v3:
* Manual Rebase (Manasi)
 Changes since v1:
 - Rename pipe timings to transcoder timings, as they are now different.
  Changes since v2:
 - Rework bigjoiner checks; always disable slave when recalculating
   master. No need to have a separate bigjoiner pass any more.
 - Use pipe_mode instead of transcoder_mode, to clean up the code.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
[vsyrjala:
* hskew isn't a thing
* Do the dsc compute if bigjoiner is enabled, not the other way around]
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Animesh Manna <animesh.manna@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201117194718.11462-4-manasi.d.navare@intel.com

drivers/gpu/drm/i915/display/intel_display.c

@@ -8194,6 +8194,19 @@ static int intel_crtc_compute_config(struct intel_crtc *crtc,
 	int clock_limit = dev_priv->max_dotclk_freq;
 
 	drm_mode_copy(pipe_mode, &pipe_config->hw.adjusted_mode);
+
+	/* Adjust pipe_mode for bigjoiner, with half the horizontal mode */
+	if (pipe_config->bigjoiner) {
+		pipe_mode->crtc_clock /= 2;
+		pipe_mode->crtc_hdisplay /= 2;
+		pipe_mode->crtc_hblank_start /= 2;
+		pipe_mode->crtc_hblank_end /= 2;
+		pipe_mode->crtc_hsync_start /= 2;
+		pipe_mode->crtc_hsync_end /= 2;
+		pipe_mode->crtc_htotal /= 2;
+		pipe_config->pipe_src_w /= 2;
+	}
+
 	intel_mode_from_crtc_timings(pipe_mode, pipe_mode);
 
 	if (INTEL_GEN(dev_priv) < 4) {
@@ -12917,6 +12930,7 @@ static int intel_crtc_atomic_check(struct intel_atomic_state *state,
 
 	if (mode_changed && crtc_state->hw.enable &&
 	    dev_priv->display.crtc_compute_clock &&
+	    !crtc_state->bigjoiner_slave &&
 	    !drm_WARN_ON(&dev_priv->drm, crtc_state->shared_dpll)) {
 		ret = dev_priv->display.crtc_compute_clock(crtc, crtc_state);
 		if (ret)
@@ -13462,6 +13476,15 @@ intel_crtc_copy_uapi_to_hw_state_nomodeset(struct intel_atomic_state *state,
 {
 	const struct intel_crtc_state *from_crtc_state = crtc_state;
 
+	if (crtc_state->bigjoiner_slave) {
+		from_crtc_state = intel_atomic_get_new_crtc_state(state,
+								  crtc_state->bigjoiner_linked_crtc);
+
+		/* No need to copy state if the master state is unchanged */
+		if (!from_crtc_state)
+			return;
+	}
+
 	intel_crtc_copy_color_blobs(crtc_state, from_crtc_state);
 }
 
@@ -13497,6 +13520,47 @@ static void intel_crtc_copy_hw_to_uapi_state(struct intel_crtc_state *crtc_state
 				  crtc_state->hw.ctm);
 }
 
+static int
+copy_bigjoiner_crtc_state(struct intel_crtc_state *crtc_state,
+			  const struct intel_crtc_state *from_crtc_state)
+{
+	struct intel_crtc_state *saved_state;
+	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
+
+	saved_state = kmemdup(from_crtc_state, sizeof(*saved_state), GFP_KERNEL);
+	if (!saved_state)
+		return -ENOMEM;
+
+	saved_state->uapi = crtc_state->uapi;
+	saved_state->scaler_state = crtc_state->scaler_state;
+	saved_state->shared_dpll = crtc_state->shared_dpll;
+	saved_state->dpll_hw_state = crtc_state->dpll_hw_state;
+	saved_state->crc_enabled = crtc_state->crc_enabled;
+
+	intel_crtc_free_hw_state(crtc_state);
+	memcpy(crtc_state, saved_state, sizeof(*crtc_state));
+	kfree(saved_state);
+
+	/* Re-init hw state */
+	memset(&crtc_state->hw, 0, sizeof(saved_state->hw));
+	crtc_state->hw.enable = from_crtc_state->hw.enable;
+	crtc_state->hw.active = from_crtc_state->hw.active;
+	crtc_state->hw.pipe_mode = from_crtc_state->hw.pipe_mode;
+	crtc_state->hw.adjusted_mode = from_crtc_state->hw.adjusted_mode;
+
+	/* Some fixups */
+	crtc_state->uapi.mode_changed = from_crtc_state->uapi.mode_changed;
+	crtc_state->uapi.connectors_changed = from_crtc_state->uapi.connectors_changed;
+	crtc_state->uapi.active_changed = from_crtc_state->uapi.active_changed;
+	crtc_state->nv12_planes = crtc_state->c8_planes = crtc_state->update_planes = 0;
+	crtc_state->bigjoiner_linked_crtc = to_intel_crtc(from_crtc_state->uapi.crtc);
+	crtc_state->bigjoiner_slave = true;
+	crtc_state->cpu_transcoder = (enum transcoder)crtc->pipe;
+	crtc_state->has_audio = false;
+
+	return 0;
+}
+
 static int
 intel_crtc_prepare_cleared_state(struct intel_atomic_state *state,
 				 struct intel_crtc_state *crtc_state)
@@ -15079,6 +15143,75 @@ static bool intel_cpu_transcoders_need_modeset(struct intel_atomic_state *state,
 	return false;
 }
 
+static int intel_atomic_check_bigjoiner(struct intel_atomic_state *state,
+					struct intel_crtc *crtc,
+					struct intel_crtc_state *old_crtc_state,
+					struct intel_crtc_state *new_crtc_state)
+{
+	struct drm_i915_private *dev_priv = to_i915(state->base.dev);
+	struct intel_crtc_state *slave_crtc_state, *master_crtc_state;
+	struct intel_crtc *slave, *master;
+
+	/* slave being enabled, is master is still claiming this crtc? */
+	if (old_crtc_state->bigjoiner_slave) {
+		slave = crtc;
+		master = old_crtc_state->bigjoiner_linked_crtc;
+		master_crtc_state = intel_atomic_get_new_crtc_state(state, master);
+		if (!master_crtc_state || !needs_modeset(master_crtc_state))
+			goto claimed;
+	}
+
+	if (!new_crtc_state->bigjoiner)
+		return 0;
+
+	if (1 + crtc->pipe >= INTEL_NUM_PIPES(dev_priv)) {
+		DRM_DEBUG_KMS("[CRTC:%d:%s] Big joiner configuration requires "
+			      "CRTC + 1 to be used, doesn't exist\n",
+			      crtc->base.base.id, crtc->base.name);
+		return -EINVAL;
+	}
+
+	slave = new_crtc_state->bigjoiner_linked_crtc =
+		intel_get_crtc_for_pipe(dev_priv, crtc->pipe + 1);
+	slave_crtc_state = intel_atomic_get_crtc_state(&state->base, slave);
+	master = crtc;
+	if (IS_ERR(slave_crtc_state))
+		return PTR_ERR(slave_crtc_state);
+
+	/* master being enabled, slave was already configured? */
+	if (slave_crtc_state->uapi.enable)
+		goto claimed;
+
+	DRM_DEBUG_KMS("[CRTC:%d:%s] Used as slave for big joiner\n",
+		      slave->base.base.id, slave->base.name);
+
+	return copy_bigjoiner_crtc_state(slave_crtc_state, new_crtc_state);
+
+claimed:
+	DRM_DEBUG_KMS("[CRTC:%d:%s] Slave is enabled as normal CRTC, but "
+		      "[CRTC:%d:%s] claiming this CRTC for bigjoiner.\n",
+		      slave->base.base.id, slave->base.name,
+		      master->base.base.id, master->base.name);
+	return -EINVAL;
+}
+
+static int kill_bigjoiner_slave(struct intel_atomic_state *state,
+				struct intel_crtc_state *master_crtc_state)
+{
+	struct intel_crtc_state *slave_crtc_state =
+			intel_atomic_get_crtc_state(&state->base,
+						    master_crtc_state->bigjoiner_linked_crtc);
+
+		if (IS_ERR(slave_crtc_state))
+			return PTR_ERR(slave_crtc_state);
+
+		slave_crtc_state->bigjoiner = master_crtc_state->bigjoiner = false;
+		slave_crtc_state->bigjoiner_slave = master_crtc_state->bigjoiner_slave = false;
+		slave_crtc_state->bigjoiner_linked_crtc = master_crtc_state->bigjoiner_linked_crtc = NULL;
+		intel_crtc_copy_uapi_to_hw_state(state, slave_crtc_state);
+		return 0;
+}
+
 /**
  * DOC: asynchronous flip implementation
  *
@@ -15246,16 +15379,33 @@ static int intel_atomic_check(struct drm_device *dev,
 			continue;
 		}
 
+		/* Kill old bigjoiner link, we may re-establish afterwards */
+		if (old_crtc_state->bigjoiner && !old_crtc_state->bigjoiner_slave) {
+			ret = kill_bigjoiner_slave(state, new_crtc_state);
+			if (ret)
+				goto fail;
+		}
+
+		if (!new_crtc_state->uapi.enable) {
+			if (!new_crtc_state->bigjoiner_slave) {
+				intel_crtc_copy_uapi_to_hw_state(state, new_crtc_state);
+				any_ms = true;
+			}
+			continue;
+		}
+
 		ret = intel_crtc_prepare_cleared_state(state, new_crtc_state);
 		if (ret)
 			goto fail;
 
-		if (!new_crtc_state->hw.enable)
-			continue;
-
 		ret = intel_modeset_pipe_config(state, new_crtc_state);
 		if (ret)
 			goto fail;
+
+		ret = intel_atomic_check_bigjoiner(state, crtc, old_crtc_state,
+						   new_crtc_state);
+		if (ret)
+			goto fail;
 	}
 
 	for_each_oldnew_intel_crtc_in_state(state, crtc, old_crtc_state,

drivers/gpu/drm/i915/display/intel_display_types.h

@@ -1079,6 +1079,15 @@ struct intel_crtc_state {
 	/* enable pipe csc? */
 	bool csc_enable;
 
+	/* enable pipe big joiner? */
+	bool bigjoiner;
+
+	/* big joiner slave crtc? */
+	bool bigjoiner_slave;
+
+	/* linked crtc for bigjoiner, either slave or master */
+	struct intel_crtc *bigjoiner_linked_crtc;
+
 	/* Display Stream compression state */
 	struct {
 		bool compression_enable;

drivers/gpu/drm/i915/display/intel_dp.c

@@ -2403,12 +2403,12 @@ static int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
 						    pipe_config->lane_count,
 						    adjusted_mode->crtc_clock,
 						    adjusted_mode->crtc_hdisplay,
-						    false);
+						    pipe_config->bigjoiner);
 		dsc_dp_slice_count =
 			intel_dp_dsc_get_slice_count(intel_dp,
 						     adjusted_mode->crtc_clock,
 						     adjusted_mode->crtc_hdisplay,
-						     false);
+						     pipe_config->bigjoiner);
 		if (!dsc_max_output_bpp || !dsc_dp_slice_count) {
 			drm_dbg_kms(&dev_priv->drm,
 				    "Compressed BPP/Slice Count not supported\n");
@@ -2424,14 +2424,15 @@ static int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
 	 * is greater than the maximum Cdclock and if slice count is even
 	 * then we need to use 2 VDSC instances.
 	 */
-	if (adjusted_mode->crtc_clock > dev_priv->max_cdclk_freq) {
-		if (pipe_config->dsc.slice_count > 1) {
-			pipe_config->dsc.dsc_split = true;
-		} else {
+	if (adjusted_mode->crtc_clock > dev_priv->max_cdclk_freq ||
+	    pipe_config->bigjoiner) {
+		if (pipe_config->dsc.slice_count < 2) {
 			drm_dbg_kms(&dev_priv->drm,
 				    "Cannot split stream to use 2 VDSC instances\n");
 			return -EINVAL;
 		}
+
+		pipe_config->dsc.dsc_split = true;
 	}
 
 	ret = intel_dp_dsc_compute_params(&dig_port->base, pipe_config);
@@ -2502,6 +2503,11 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
 		    intel_dp->common_rates[limits.max_clock],
 		    limits.max_bpp, adjusted_mode->crtc_clock);
 
+	if ((adjusted_mode->crtc_clock > i915->max_dotclk_freq ||
+	     adjusted_mode->crtc_hdisplay > 5120) &&
+	    intel_dp_can_bigjoiner(intel_dp))
+		pipe_config->bigjoiner = true;
+
 	/*
 	 * Optimize for slow and wide. This is the place to add alternative
 	 * optimization policy.
@@ -2510,7 +2516,7 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
 
 	/* enable compression if the mode doesn't fit available BW */
 	drm_dbg_kms(&i915->drm, "Force DSC en = %d\n", intel_dp->force_dsc_en);
-	if (ret || intel_dp->force_dsc_en) {
+	if (ret || intel_dp->force_dsc_en || pipe_config->bigjoiner) {
 		ret = intel_dp_dsc_compute_config(intel_dp, pipe_config,
 						  conn_state, &limits);
 		if (ret < 0)