Merge tag 'drm-misc-fixes-2020-11-26' of ssh://git.freedesktop.org/git/drm/drm-misc into drm-fixes

A bunch of fixes for vc4 fixing some coexistence issue between wifi and
HDMI, unsupported modes, and vblank timeouts, a fix for ast to reload
the gamma LUT after changing the plane format and a double-free fix for
nouveau

Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20201126085450.r3i7wvj7pizsa4l6@gilmour

7 files changed, 271 insertions, 67 deletions

diff --git a/Documentation/devicetree/bindings/display/brcm,bcm2711-hdmi.yaml b/Documentation/devicetree/bindings/display/brcm,bcm2711-hdmi.yaml
index 03a76729d26c..7ce06f9f9f8e 100644
--- a/Documentation/devicetree/bindings/display/brcm,bcm2711-hdmi.yaml
+++ b/Documentation/devicetree/bindings/display/brcm,bcm2711-hdmi.yaml
@@ -76,6 +76,12 @@ properties:
   resets:
     maxItems: 1
 
+  wifi-2.4ghz-coexistence:
+    type: boolean
+    description: >
+      Should the pixel frequencies in the WiFi frequencies range be
+      avoided?
+
 required:
   - compatible
   - reg
diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
index 834a156e3a75..0a1e1cf57e19 100644
--- a/drivers/gpu/drm/ast/ast_mode.c
+++ b/drivers/gpu/drm/ast/ast_mode.c
@@ -742,7 +742,6 @@ static void ast_crtc_dpms(struct drm_crtc *crtc, int mode)
 	case DRM_MODE_DPMS_SUSPEND:
 		if (ast->tx_chip_type == AST_TX_DP501)
 			ast_set_dp501_video_output(crtc->dev, 1);
-		ast_crtc_load_lut(ast, crtc);
 		break;
 	case DRM_MODE_DPMS_OFF:
 		if (ast->tx_chip_type == AST_TX_DP501)
@@ -778,6 +777,21 @@ static int ast_crtc_helper_atomic_check(struct drm_crtc *crtc,
 }
 
 static void
+ast_crtc_helper_atomic_flush(struct drm_crtc *crtc, struct drm_crtc_state *old_crtc_state)
+{
+	struct ast_private *ast = to_ast_private(crtc->dev);
+	struct ast_crtc_state *ast_crtc_state = to_ast_crtc_state(crtc->state);
+	struct ast_crtc_state *old_ast_crtc_state = to_ast_crtc_state(old_crtc_state);
+
+	/*
+	 * The gamma LUT has to be reloaded after changing the primary
+	 * plane's color format.
+	 */
+	if (old_ast_crtc_state->format != ast_crtc_state->format)
+		ast_crtc_load_lut(ast, crtc);
+}
+
+static void
 ast_crtc_helper_atomic_enable(struct drm_crtc *crtc,
 			      struct drm_crtc_state *old_crtc_state)
 {
@@ -830,6 +844,7 @@ ast_crtc_helper_atomic_disable(struct drm_crtc *crtc,
 
 static const struct drm_crtc_helper_funcs ast_crtc_helper_funcs = {
 	.atomic_check = ast_crtc_helper_atomic_check,
+	.atomic_flush = ast_crtc_helper_atomic_flush,
 	.atomic_enable = ast_crtc_helper_atomic_enable,
 	.atomic_disable = ast_crtc_helper_atomic_disable,
 };
diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c b/drivers/gpu/drm/nouveau/nouveau_gem.c
index 549bc67feabb..c2051380d18c 100644
--- a/drivers/gpu/drm/nouveau/nouveau_gem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_gem.c
@@ -558,8 +558,10 @@ nouveau_gem_pushbuf_validate(struct nouveau_channel *chan,
 			NV_PRINTK(err, cli, "validating bo list\n");
 		validate_fini(op, chan, NULL, NULL);
 		return ret;
+	} else if (ret > 0) {
+		*apply_relocs = true;
 	}
-	*apply_relocs = ret;
+
 	return 0;
 }
 
@@ -662,7 +664,6 @@ nouveau_gem_pushbuf_reloc_apply(struct nouveau_cli *cli,
 		nouveau_bo_wr32(nvbo, r->reloc_bo_offset >> 2, data);
 	}
 
-	u_free(reloc);
 	return ret;
 }
 
@@ -872,9 +873,10 @@ out:
 				break;
 			}
 		}
-		u_free(reloc);
 	}
 out_prevalid:
+	if (!IS_ERR(reloc))
+		u_free(reloc);
 	u_free(bo);
 	u_free(push);
 
diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
index 19b75bebd35f..c5f2944d5bc6 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.h
+++ b/drivers/gpu/drm/vc4/vc4_drv.h
@@ -219,6 +219,7 @@ struct vc4_dev {
 
 	struct drm_modeset_lock ctm_state_lock;
 	struct drm_private_obj ctm_manager;
+	struct drm_private_obj hvs_channels;
 	struct drm_private_obj load_tracker;
 
 	/* List of vc4_debugfs_info_entry for adding to debugfs once
@@ -531,6 +532,9 @@ struct vc4_crtc_state {
 		unsigned int top;
 		unsigned int bottom;
 	} margins;
+
+	/* Transitional state below, only valid during atomic commits */
+	bool update_muxing;
 };
 
 #define VC4_HVS_CHANNEL_DISABLED ((unsigned int)-1)
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index 95779d50cca0..afc178b0d89f 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -760,12 +760,54 @@ static void vc4_hdmi_encoder_enable(struct drm_encoder *encoder)
 {
 }
 
+#define WIFI_2_4GHz_CH1_MIN_FREQ	2400000000ULL
+#define WIFI_2_4GHz_CH1_MAX_FREQ	2422000000ULL
+
+static int vc4_hdmi_encoder_atomic_check(struct drm_encoder *encoder,
+					 struct drm_crtc_state *crtc_state,
+					 struct drm_connector_state *conn_state)
+{
+	struct drm_display_mode *mode = &crtc_state->adjusted_mode;
+	struct vc4_hdmi *vc4_hdmi = encoder_to_vc4_hdmi(encoder);
+	unsigned long long pixel_rate = mode->clock * 1000;
+	unsigned long long tmds_rate;
+
+	if (vc4_hdmi->variant->unsupported_odd_h_timings &&
+	    ((mode->hdisplay % 2) || (mode->hsync_start % 2) ||
+	     (mode->hsync_end % 2) || (mode->htotal % 2)))
+		return -EINVAL;
+
+	/*
+	 * The 1440p@60 pixel rate is in the same range than the first
+	 * WiFi channel (between 2.4GHz and 2.422GHz with 22MHz
+	 * bandwidth). Slightly lower the frequency to bring it out of
+	 * the WiFi range.
+	 */
+	tmds_rate = pixel_rate * 10;
+	if (vc4_hdmi->disable_wifi_frequencies &&
+	    (tmds_rate >= WIFI_2_4GHz_CH1_MIN_FREQ &&
+	     tmds_rate <= WIFI_2_4GHz_CH1_MAX_FREQ)) {
+		mode->clock = 238560;
+		pixel_rate = mode->clock * 1000;
+	}
+
+	if (pixel_rate > vc4_hdmi->variant->max_pixel_clock)
+		return -EINVAL;
+
+	return 0;
+}
+
 static enum drm_mode_status
 vc4_hdmi_encoder_mode_valid(struct drm_encoder *encoder,
 			    const struct drm_display_mode *mode)
 {
 	struct vc4_hdmi *vc4_hdmi = encoder_to_vc4_hdmi(encoder);
 
+	if (vc4_hdmi->variant->unsupported_odd_h_timings &&
+	    ((mode->hdisplay % 2) || (mode->hsync_start % 2) ||
+	     (mode->hsync_end % 2) || (mode->htotal % 2)))
+		return MODE_H_ILLEGAL;
+
 	if ((mode->clock * 1000) > vc4_hdmi->variant->max_pixel_clock)
 		return MODE_CLOCK_HIGH;
 
@@ -773,6 +815,7 @@ vc4_hdmi_encoder_mode_valid(struct drm_encoder *encoder,
 }
 
 static const struct drm_encoder_helper_funcs vc4_hdmi_encoder_helper_funcs = {
+	.atomic_check = vc4_hdmi_encoder_atomic_check,
 	.mode_valid = vc4_hdmi_encoder_mode_valid,
 	.disable = vc4_hdmi_encoder_disable,
 	.enable = vc4_hdmi_encoder_enable,
@@ -1694,6 +1737,9 @@ static int vc4_hdmi_bind(struct device *dev, struct device *master, void *data)
 		vc4_hdmi->hpd_active_low = hpd_gpio_flags & OF_GPIO_ACTIVE_LOW;
 	}
 
+	vc4_hdmi->disable_wifi_frequencies =
+		of_property_read_bool(dev->of_node, "wifi-2.4ghz-coexistence");
+
 	pm_runtime_enable(dev);
 
 	drm_simple_encoder_init(drm, encoder, DRM_MODE_ENCODER_TMDS);
@@ -1817,6 +1863,7 @@ static const struct vc4_hdmi_variant bcm2711_hdmi0_variant = {
 		PHY_LANE_2,
 		PHY_LANE_CK,
 	},
+	.unsupported_odd_h_timings	= true,
 
 	.init_resources		= vc5_hdmi_init_resources,
 	.csc_setup		= vc5_hdmi_csc_setup,
@@ -1842,6 +1889,7 @@ static const struct vc4_hdmi_variant bcm2711_hdmi1_variant = {
 		PHY_LANE_CK,
 		PHY_LANE_2,
 	},
+	.unsupported_odd_h_timings	= true,
 
 	.init_resources		= vc5_hdmi_init_resources,
 	.csc_setup		= vc5_hdmi_csc_setup,
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.h b/drivers/gpu/drm/vc4/vc4_hdmi.h
index 63c6f8bddf1d..0526a9cf608a 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.h
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.h
@@ -62,6 +62,9 @@ struct vc4_hdmi_variant {
 	 */
 	enum vc4_hdmi_phy_channel phy_lane_mapping[4];
 
+	/* The BCM2711 cannot deal with odd horizontal pixel timings */
+	bool unsupported_odd_h_timings;
+
 	/* Callback to get the resources (memory region, interrupts,
 	 * clocks, etc) for that variant.
 	 */
@@ -139,6 +142,14 @@ struct vc4_hdmi {
 	int hpd_gpio;
 	bool hpd_active_low;
 
+	/*
+	 * On some systems (like the RPi4), some modes are in the same
+	 * frequency range than the WiFi channels (1440p@60Hz for
+	 * example). Should we take evasive actions because that system
+	 * has a wifi adapter?
+	 */
+	bool disable_wifi_frequencies;
+
 	struct cec_adapter *cec_adap;
 	struct cec_msg cec_rx_msg;
 	bool cec_tx_ok;
diff --git a/drivers/gpu/drm/vc4/vc4_kms.c b/drivers/gpu/drm/vc4/vc4_kms.c
index 2b951cae04ad..ba310c0ab5f6 100644
--- a/drivers/gpu/drm/vc4/vc4_kms.c
+++ b/drivers/gpu/drm/vc4/vc4_kms.c
@@ -24,6 +24,8 @@
 #include "vc4_drv.h"
 #include "vc4_regs.h"
 
+#define HVS_NUM_CHANNELS 3
+
 struct vc4_ctm_state {
 	struct drm_private_state base;
 	struct drm_color_ctm *ctm;
@@ -35,6 +37,17 @@ static struct vc4_ctm_state *to_vc4_ctm_state(struct drm_private_state *priv)
 	return container_of(priv, struct vc4_ctm_state, base);
 }
 
+struct vc4_hvs_state {
+	struct drm_private_state base;
+	unsigned int unassigned_channels;
+};
+
+static struct vc4_hvs_state *
+to_vc4_hvs_state(struct drm_private_state *priv)
+{
+	return container_of(priv, struct vc4_hvs_state, base);
+}
+
 struct vc4_load_tracker_state {
 	struct drm_private_state base;
 	u64 hvs_load;
@@ -113,7 +126,7 @@ static int vc4_ctm_obj_init(struct vc4_dev *vc4)
 	drm_atomic_private_obj_init(&vc4->base, &vc4->ctm_manager, &ctm_state->base,
 				    &vc4_ctm_state_funcs);
 
-	return drmm_add_action(&vc4->base, vc4_ctm_obj_fini, NULL);
+	return drmm_add_action_or_reset(&vc4->base, vc4_ctm_obj_fini, NULL);
 }
 
 /* Converts a DRM S31.32 value to the HW S0.9 format. */
@@ -169,6 +182,19 @@ vc4_ctm_commit(struct vc4_dev *vc4, struct drm_atomic_state *state)
 		  VC4_SET_FIELD(ctm_state->fifo, SCALER_OLEDOFFS_DISPFIFO));
 }
 
+static struct vc4_hvs_state *
+vc4_hvs_get_global_state(struct drm_atomic_state *state)
+{
+	struct vc4_dev *vc4 = to_vc4_dev(state->dev);
+	struct drm_private_state *priv_state;
+
+	priv_state = drm_atomic_get_private_obj_state(state, &vc4->hvs_channels);
+	if (IS_ERR(priv_state))
+		return ERR_CAST(priv_state);
+
+	return to_vc4_hvs_state(priv_state);
+}
+
 static void vc4_hvs_pv_muxing_commit(struct vc4_dev *vc4,
 				     struct drm_atomic_state *state)
 {
@@ -213,10 +239,7 @@ static void vc5_hvs_pv_muxing_commit(struct vc4_dev *vc4,
 {
 	struct drm_crtc_state *crtc_state;
 	struct drm_crtc *crtc;
-	unsigned char dsp2_mux = 0;
-	unsigned char dsp3_mux = 3;
-	unsigned char dsp4_mux = 3;
-	unsigned char dsp5_mux = 3;
+	unsigned char mux;
 	unsigned int i;
 	u32 reg;
 
@@ -224,50 +247,59 @@ static void vc5_hvs_pv_muxing_commit(struct vc4_dev *vc4,
 		struct vc4_crtc_state *vc4_state = to_vc4_crtc_state(crtc_state);
 		struct vc4_crtc *vc4_crtc = to_vc4_crtc(crtc);
 
-		if (!crtc_state->active)
+		if (!vc4_state->update_muxing)
 			continue;
 
 		switch (vc4_crtc->data->hvs_output) {
 		case 2:
-			dsp2_mux = (vc4_state->assigned_channel == 2) ? 0 : 1;
+			mux = (vc4_state->assigned_channel == 2) ? 0 : 1;
+			reg = HVS_READ(SCALER_DISPECTRL);
+			HVS_WRITE(SCALER_DISPECTRL,
+				  (reg & ~SCALER_DISPECTRL_DSP2_MUX_MASK) |
+				  VC4_SET_FIELD(mux, SCALER_DISPECTRL_DSP2_MUX));
 			break;
 
 		case 3:
-			dsp3_mux = vc4_state->assigned_channel;
+			if (vc4_state->assigned_channel == VC4_HVS_CHANNEL_DISABLED)
+				mux = 3;
+			else
+				mux = vc4_state->assigned_channel;
+
+			reg = HVS_READ(SCALER_DISPCTRL);
+			HVS_WRITE(SCALER_DISPCTRL,
+				  (reg & ~SCALER_DISPCTRL_DSP3_MUX_MASK) |
+				  VC4_SET_FIELD(mux, SCALER_DISPCTRL_DSP3_MUX));
 			break;
 
 		case 4:
-			dsp4_mux = vc4_state->assigned_channel;
+			if (vc4_state->assigned_channel == VC4_HVS_CHANNEL_DISABLED)
+				mux = 3;
+			else
+				mux = vc4_state->assigned_channel;
+
+			reg = HVS_READ(SCALER_DISPEOLN);
+			HVS_WRITE(SCALER_DISPEOLN,
+				  (reg & ~SCALER_DISPEOLN_DSP4_MUX_MASK) |
+				  VC4_SET_FIELD(mux, SCALER_DISPEOLN_DSP4_MUX));
+
 			break;
 
 		case 5:
-			dsp5_mux = vc4_state->assigned_channel;
+			if (vc4_state->assigned_channel == VC4_HVS_CHANNEL_DISABLED)
+				mux = 3;
+			else
+				mux = vc4_state->assigned_channel;
+
+			reg = HVS_READ(SCALER_DISPDITHER);
+			HVS_WRITE(SCALER_DISPDITHER,
+				  (reg & ~SCALER_DISPDITHER_DSP5_MUX_MASK) |
+				  VC4_SET_FIELD(mux, SCALER_DISPDITHER_DSP5_MUX));
 			break;
 
 		default:
 			break;
 		}
 	}
-
-	reg = HVS_READ(SCALER_DISPECTRL);
-	HVS_WRITE(SCALER_DISPECTRL,
-		  (reg & ~SCALER_DISPECTRL_DSP2_MUX_MASK) |
-		  VC4_SET_FIELD(dsp2_mux, SCALER_DISPECTRL_DSP2_MUX));
-
-	reg = HVS_READ(SCALER_DISPCTRL);
-	HVS_WRITE(SCALER_DISPCTRL,
-		  (reg & ~SCALER_DISPCTRL_DSP3_MUX_MASK) |
-		  VC4_SET_FIELD(dsp3_mux, SCALER_DISPCTRL_DSP3_MUX));
-
-	reg = HVS_READ(SCALER_DISPEOLN);
-	HVS_WRITE(SCALER_DISPEOLN,
-		  (reg & ~SCALER_DISPEOLN_DSP4_MUX_MASK) |
-		  VC4_SET_FIELD(dsp4_mux, SCALER_DISPEOLN_DSP4_MUX));
-
-	reg = HVS_READ(SCALER_DISPDITHER);
-	HVS_WRITE(SCALER_DISPDITHER,
-		  (reg & ~SCALER_DISPDITHER_DSP5_MUX_MASK) |
-		  VC4_SET_FIELD(dsp5_mux, SCALER_DISPDITHER_DSP5_MUX));
 }
 
 static void
@@ -657,53 +689,123 @@ static int vc4_load_tracker_obj_init(struct vc4_dev *vc4)
 				    &load_state->base,
 				    &vc4_load_tracker_state_funcs);
 
-	return drmm_add_action(&vc4->base, vc4_load_tracker_obj_fini, NULL);
+	return drmm_add_action_or_reset(&vc4->base, vc4_load_tracker_obj_fini, NULL);
 }
 
-#define NUM_OUTPUTS  6
-#define NUM_CHANNELS 3
+static struct drm_private_state *
+vc4_hvs_channels_duplicate_state(struct drm_private_obj *obj)
+{
+	struct vc4_hvs_state *old_state = to_vc4_hvs_state(obj->state);
+	struct vc4_hvs_state *state;
+
+	state = kzalloc(sizeof(*state), GFP_KERNEL);
+	if (!state)
+		return NULL;
 
-static int
-vc4_atomic_check(struct drm_device *dev, struct drm_atomic_state *state)
+	__drm_atomic_helper_private_obj_duplicate_state(obj, &state->base);
+
+	state->unassigned_channels = old_state->unassigned_channels;
+
+	return &state->base;
+}
+
+static void vc4_hvs_channels_destroy_state(struct drm_private_obj *obj,
+					   struct drm_private_state *state)
 {
-	unsigned long unassigned_channels = GENMASK(NUM_CHANNELS - 1, 0);
-	struct drm_crtc_state *old_crtc_state, *new_crtc_state;
-	struct drm_crtc *crtc;
-	int i, ret;
+	struct vc4_hvs_state *hvs_state = to_vc4_hvs_state(state);
 
-	/*
-	 * Since the HVS FIFOs are shared across all the pixelvalves and
-	 * the TXP (and thus all the CRTCs), we need to pull the current
-	 * state of all the enabled CRTCs so that an update to a single
-	 * CRTC still keeps the previous FIFOs enabled and assigned to
-	 * the same CRTCs, instead of evaluating only the CRTC being
-	 * modified.
-	 */
-	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
-		struct drm_crtc_state *crtc_state;
+	kfree(hvs_state);
+}
 
-		if (!crtc->state->enable)
-			continue;
+static const struct drm_private_state_funcs vc4_hvs_state_funcs = {
+	.atomic_duplicate_state = vc4_hvs_channels_duplicate_state,
+	.atomic_destroy_state = vc4_hvs_channels_destroy_state,
+};
 
-		crtc_state = drm_atomic_get_crtc_state(state, crtc);
-		if (IS_ERR(crtc_state))
-			return PTR_ERR(crtc_state);
-	}
+static void vc4_hvs_channels_obj_fini(struct drm_device *dev, void *unused)
+{
+	struct vc4_dev *vc4 = to_vc4_dev(dev);
+
+	drm_atomic_private_obj_fini(&vc4->hvs_channels);
+}
+
+static int vc4_hvs_channels_obj_init(struct vc4_dev *vc4)
+{
+	struct vc4_hvs_state *state;
+
+	state = kzalloc(sizeof(*state), GFP_KERNEL);
+	if (!state)
+		return -ENOMEM;
+
+	state->unassigned_channels = GENMASK(HVS_NUM_CHANNELS - 1, 0);
+	drm_atomic_private_obj_init(&vc4->base, &vc4->hvs_channels,
+				    &state->base,
+				    &vc4_hvs_state_funcs);
+
+	return drmm_add_action_or_reset(&vc4->base, vc4_hvs_channels_obj_fini, NULL);
+}
+
+/*
+ * The BCM2711 HVS has up to 7 outputs connected to the pixelvalves and
+ * the TXP (and therefore all the CRTCs found on that platform).
+ *
+ * The naive (and our initial) implementation would just iterate over
+ * all the active CRTCs, try to find a suitable FIFO, and then remove it
+ * from the pool of available FIFOs. However, there are a few corner
+ * cases that need to be considered:
+ *
+ * - When running in a dual-display setup (so with two CRTCs involved),
+ *   we can update the state of a single CRTC (for example by changing
+ *   its mode using xrandr under X11) without affecting the other. In
+ *   this case, the other CRTC wouldn't be in the state at all, so we
+ *   need to consider all the running CRTCs in the DRM device to assign
+ *   a FIFO, not just the one in the state.
+ *
+ * - To fix the above, we can't use drm_atomic_get_crtc_state on all
+ *   enabled CRTCs to pull their CRTC state into the global state, since
+ *   a page flip would start considering their vblank to complete. Since
+ *   we don't have a guarantee that they are actually active, that
+ *   vblank might never happen, and shouldn't even be considered if we
+ *   want to do a page flip on a single CRTC. That can be tested by
+ *   doing a modetest -v first on HDMI1 and then on HDMI0.
+ *
+ * - Since we need the pixelvalve to be disabled and enabled back when
+ *   the FIFO is changed, we should keep the FIFO assigned for as long
+ *   as the CRTC is enabled, only considering it free again once that
+ *   CRTC has been disabled. This can be tested by booting X11 on a
+ *   single display, and changing the resolution down and then back up.
+ */
+static int vc4_pv_muxing_atomic_check(struct drm_device *dev,
+				      struct drm_atomic_state *state)
+{
+	struct vc4_hvs_state *hvs_new_state;
+	struct drm_crtc_state *old_crtc_state, *new_crtc_state;
+	struct drm_crtc *crtc;
+	unsigned int i;
+
+	hvs_new_state = vc4_hvs_get_global_state(state);
+	if (!hvs_new_state)
+		return -EINVAL;
 
 	for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, new_crtc_state, i) {
+		struct vc4_crtc_state *old_vc4_crtc_state =
+			to_vc4_crtc_state(old_crtc_state);
 		struct vc4_crtc_state *new_vc4_crtc_state =
 			to_vc4_crtc_state(new_crtc_state);
 		struct vc4_crtc *vc4_crtc = to_vc4_crtc(crtc);
 		unsigned int matching_channels;
 
-		if (old_crtc_state->enable && !new_crtc_state->enable)
-			new_vc4_crtc_state->assigned_channel = VC4_HVS_CHANNEL_DISABLED;
-
-		if (!new_crtc_state->enable)
+		/* Nothing to do here, let's skip it */
+		if (old_crtc_state->enable == new_crtc_state->enable)
 			continue;
 
-		if (new_vc4_crtc_state->assigned_channel != VC4_HVS_CHANNEL_DISABLED) {
-			unassigned_channels &= ~BIT(new_vc4_crtc_state->assigned_channel);
+		/* Muxing will need to be modified, mark it as such */
+		new_vc4_crtc_state->update_muxing = true;
+
+		/* If we're disabling our CRTC, we put back our channel */
+		if (!new_crtc_state->enable) {
+			hvs_new_state->unassigned_channels |= BIT(old_vc4_crtc_state->assigned_channel);
+			new_vc4_crtc_state->assigned_channel = VC4_HVS_CHANNEL_DISABLED;
 			continue;
 		}
 
@@ -731,17 +833,29 @@ vc4_atomic_check(struct drm_device *dev, struct drm_atomic_state *state)
 		 * the future, we will need to have something smarter,
 		 * but it works so far.
 		 */
-		matching_channels = unassigned_channels & vc4_crtc->data->hvs_available_channels;
+		matching_channels = hvs_new_state->unassigned_channels & vc4_crtc->data->hvs_available_channels;
 		if (matching_channels) {
 			unsigned int channel = ffs(matching_channels) - 1;
 
 			new_vc4_crtc_state->assigned_channel = channel;
-			unassigned_channels &= ~BIT(channel);
+			hvs_new_state->unassigned_channels &= ~BIT(channel);
 		} else {
 			return -EINVAL;
 		}
 	}
 
+	return 0;
+}
+
+static int
+vc4_atomic_check(struct drm_device *dev, struct drm_atomic_state *state)
+{
+	int ret;
+
+	ret = vc4_pv_muxing_atomic_check(dev, state);
+	if (ret)
+		return ret;
+
 	ret = vc4_ctm_atomic_check(dev, state);
 	if (ret < 0)
 		return ret;
@@ -808,6 +922,10 @@ int vc4_kms_load(struct drm_device *dev)
 	if (ret)
 		return ret;
 
+	ret = vc4_hvs_channels_obj_init(vc4);
+	if (ret)
+		return ret;
+
 	drm_mode_config_reset(dev);
 
 	drm_kms_helper_poll_init(dev);