1 files changed, 40 insertions, 0 deletions
diff --git a/target/linux/bcm27xx/patches-5.15/950-0006-drm-vc4-hdmi-Fix-HPD-GPIO-detection.patch b/target/linux/bcm27xx/patches-5.15/950-0006-drm-vc4-hdmi-Fix-HPD-GPIO-detection.patch
new file mode 100644
index 0000000000..bfc2ed4e8b
--- /dev/null
+++ b/target/linux/bcm27xx/patches-5.15/950-0006-drm-vc4-hdmi-Fix-HPD-GPIO-detection.patch
@@ -0,0 +1,40 @@
+From b460aee2dab3419842e24e7039a52d613b19a6e8 Mon Sep 17 00:00:00 2001
+From: Maxime Ripard <maxime@cerno.tech>
+Date: Mon, 25 Oct 2021 17:28:55 +0200
+Subject: [PATCH] drm/vc4: hdmi: Fix HPD GPIO detection
+
+Prior to commit 6800234ceee0 ("drm/vc4: hdmi: Convert to gpiod"), in the
+detect hook, if we had an HPD GPIO we would only rely on it and return
+whatever state it was in.
+
+However, that commit changed that by mistake to only consider the case
+where we have a GPIO and it returns a logical high, and would fall back
+to the other methods otherwise.
+
+Since we can read the EDIDs when the HPD signal is low on some displays,
+we changed the detection status from disconnected to connected, and we
+would ignore an HPD pulse.
+
+Fixes: 6800234ceee0 ("drm/vc4: hdmi: Convert to gpiod")
+Signed-off-by: Maxime Ripard <maxime@cerno.tech>
+Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
+Link: https://lore.kernel.org/r/20211025152903.1088803-3-maxime@cerno.tech
+---
+ drivers/gpu/drm/vc4/vc4_hdmi.c | 6 +++---
+ 1 file changed, 3 insertions(+), 3 deletions(-)
+
+--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
++++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
+@@ -172,9 +172,9 @@ vc4_hdmi_connector_detect(struct drm_con
+ 
+ 	WARN_ON(pm_runtime_resume_and_get(&vc4_hdmi->pdev->dev));
+ 
+-	if (vc4_hdmi->hpd_gpio &&
+-	    gpiod_get_value_cansleep(vc4_hdmi->hpd_gpio)) {
+-		connected = true;
++	if (vc4_hdmi->hpd_gpio) {
++		if (gpiod_get_value_cansleep(vc4_hdmi->hpd_gpio))
++			connected = true;
+ 	} else if (HDMI_READ(HDMI_HOTPLUG) & VC4_HDMI_HOTPLUG_CONNECTED) {
+ 		connected = true;
+ 	}