[PATCH v2 5/8] drm/vc4: hdmi: Propagate -EDEADLK to the top level

[Cristian Ciocaltea <cristian.ciocaltea@collabora.com>]

drm_connector_helper_funcs.detect_ctx() is expected to propagate
-EDEADLK so that context owners, e.g. drm_helper_probe_detect_ctx(), can
perform the required backoff and retry.

vc4_hdmi_handle_hotplug() instead runs its own retry loop and calls
drm_modeset_backoff() on an acquire context it does not own.  This drops
all locks in the context, including connection_mutex held by the core.

Drop the local retry logic and propagate -EDEADLK to the caller instead.
This aligns VC4 with the expected detect_ctx() semantics.

Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
---
 drivers/gpu/drm/vc4/vc4_hdmi.c | 23 +++++++----------------
 1 file changed, 7 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index 922a6b99891d..59af0d068457 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -344,12 +344,11 @@ static int vc4_hdmi_reset_link(struct drm_connector *connector,
 	return drm_atomic_helper_reset_crtc(crtc, ctx);
 }
 
-static void vc4_hdmi_handle_hotplug(struct vc4_hdmi *vc4_hdmi,
-				    struct drm_modeset_acquire_ctx *ctx,
-				    enum drm_connector_status status)
+static int vc4_hdmi_handle_hotplug(struct vc4_hdmi *vc4_hdmi,
+				   struct drm_modeset_acquire_ctx *ctx,
+				   enum drm_connector_status status)
 {
 	struct drm_connector *connector = &vc4_hdmi->connector;
-	int ret;
 
 	/*
 	 * NOTE: This function should really be called with vc4_hdmi->mutex
@@ -368,17 +367,9 @@ static void vc4_hdmi_handle_hotplug(struct vc4_hdmi *vc4_hdmi,
 	drm_atomic_helper_connector_hdmi_hotplug(connector, ctx, status);
 
 	if (status != connector_status_connected)
-		return;
+		return 0;
 
-	for (;;) {
-		ret = vc4_hdmi_reset_link(connector, ctx);
-		if (ret == -EDEADLK) {
-			drm_modeset_backoff(ctx);
-			continue;
-		}
-
-		break;
-	}
+	return vc4_hdmi_reset_link(connector, ctx);
 }
 
 static int vc4_hdmi_connector_detect_ctx(struct drm_connector *connector,
@@ -416,10 +407,10 @@ static int vc4_hdmi_connector_detect_ctx(struct drm_connector *connector,
 			status = connector_status_connected;
 	}
 
-	vc4_hdmi_handle_hotplug(vc4_hdmi, ctx, status);
+	ret = vc4_hdmi_handle_hotplug(vc4_hdmi, ctx, status);
 	pm_runtime_put(&vc4_hdmi->pdev->dev);
 
-	return status;
+	return ret == -EDEADLK ? ret : status;
 }
 
 static int vc4_hdmi_connector_get_modes(struct drm_connector *connector)

-- 
2.55.0