openwrt/target/linux/bcm27xx/patches-5.10/950-0717-drm-vc4-hdmi-Make-sure-the-controller-is-powered-up-.patch

From 94bc403a9a7af3bd042ecdc160e6ab0b08331df8 Mon Sep 17 00:00:00 2001
From: Maxime Ripard <maxime@cerno.tech>
Date: Fri, 2 Jul 2021 12:03:28 +0200
Subject: [PATCH] drm/vc4: hdmi: Make sure the controller is powered up during
 bind

In the bind hook, we actually need the device to have the HSM clock
running during the final part of the display initialisation where we
reset the controller and initialise the CEC component.

Failing to do so will result in a complete, silent, hang of the CPU.

Fixes: 411efa18e4b0 ("drm/vc4: hdmi: Move the HSM clock enable to runtime_pm")
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
 drivers/gpu/drm/vc4/vc4_hdmi.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -2289,6 +2289,18 @@ static int vc4_hdmi_bind(struct device *
 	vc4_hdmi->disable_wifi_frequencies =
 		of_property_read_bool(dev->of_node, "wifi-2.4ghz-coexistence");
 
+	/*
+	 * We need to have the device powered up at this point to call
+	 * our reset hook and for the CEC init.
+	 */
+	ret = vc4_hdmi_runtime_resume(dev);
+	if (ret)
+		goto err_put_ddc;
+
+	pm_runtime_get_noresume(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+
 	if (vc4_hdmi->variant->reset)
 		vc4_hdmi->variant->reset(vc4_hdmi);
 
@@ -2300,8 +2312,6 @@ static int vc4_hdmi_bind(struct device *
 		clk_prepare_enable(vc4_hdmi->pixel_bvb_clock);
 	}
 
-	pm_runtime_enable(dev);
-
 	drm_simple_encoder_init(drm, encoder, DRM_MODE_ENCODER_TMDS);
 	drm_encoder_helper_add(encoder, &vc4_hdmi_encoder_helper_funcs);
 
@@ -2325,6 +2335,8 @@ static int vc4_hdmi_bind(struct device *
 			     vc4_hdmi_debugfs_regs,
 			     vc4_hdmi);
 
+	pm_runtime_put_sync(dev);
+
 	return 0;
 
 err_free_cec:
@@ -2335,6 +2347,7 @@ err_destroy_conn:
 	vc4_hdmi_connector_destroy(&vc4_hdmi->connector);
 err_destroy_encoder:
 	drm_encoder_cleanup(encoder);
+	pm_runtime_put_sync(dev);
 	pm_runtime_disable(dev);
 err_put_ddc:
 	put_device(&vc4_hdmi->ddc->dev);