Subject: linux-next: build failure after merge of the drm tree

From: Stephen Rothwell <[email-masked]>
Date: Thu, 4 Dec 2025 15:24:03 +1100

Hi all,

After merging the drm tree, today's linux-next build (x86_64 allmodconfig)
failed like this:

drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:4026:13: error: redefinition of 'are_sinks_equal'
 4026 | static bool are_sinks_equal(const struct dc_sink *sink1, const struct dc_sink *sink2)
      |             ^~~~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:3935:13: note: previous definition of 'are_sinks_equal' with type 'bool(const struct dc_sink *, const struct dc_sink *)' {aka '_Bool(const struct dc_sink *, const struct dc_sink *)'}
 3935 | static bool are_sinks_equal(const struct dc_sink *sink1, const struct dc_sink *sink2)
      |             ^~~~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:4058:13: error: redefinition of 'hdmi_hpd_debounce_work'
 4058 | static void hdmi_hpd_debounce_work(struct work_struct *work)
      |             ^~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:3967:13: note: previous definition of 'hdmi_hpd_debounce_work' with type 'void(struct work_struct *)'
 3967 | static void hdmi_hpd_debounce_work(struct work_struct *work)
      |             ^~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:3967:13: error: 'hdmi_hpd_debounce_work' defined but not used [-Werror=unused-function]
cc1: all warnings being treated as errors

Caused by commit

  c918e75e1ed9 ("drm/amd/display: Add an HPD filter for HDMI")

merging badly with commit

  c97da4785b3b ("drm/amd/display: Add an HPD filter for HDMI")

from Linus' tree :-(

I have applied the following merge fix patch for tosay.

From 1be223e7e9978a416cbdb835ea283da95abf7b58 Mon Sep 17 00:00:00 2001
From: Stephen Rothwell <[email-masked]>
Date: Thu, 4 Dec 2025 14:43:35 +1100
Subject: [PATCH] fix up for duplicate commit "drm/amd/display: Add an HPD
 filter for HDMI"

merging badly

Signed-off-by: Stephen Rothwell <[email-masked]>
---
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 91 -------------------
 1 file changed, 91 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 8b43d49dffcd..740711ac1037 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -3949,97 +3949,6 @@ static bool are_sinks_equal(const struct dc_sink *sink1, const struct dc_sink *s
 }

-/**
- * DOC: hdmi_hpd_debounce_work
- *
- * HDMI HPD debounce delay in milliseconds. When an HDMI display toggles HPD
- * (such as during power save transitions), this delay determines how long to
- * wait before processing the HPD event. This allows distinguishing between a
- * physical unplug (>hdmi_hpd_debounce_delay)
- * and a spontaneous RX HPD toggle (<hdmi_hpd_debounce_delay).
- *
- * If the toggle is less than this delay, the driver compares sink capabilities
- * and permits a hotplug event if they changed.
- *
- * The default value of 1500ms was chosen based on experimental testing with
- * various monitors that exhibit spontaneous HPD toggling behavior.
- */
-static void hdmi_hpd_debounce_work(struct work_struct *work)
-{
-	struct amdgpu_dm_connector *aconnector =
-		container_of(to_delayed_work(work), struct amdgpu_dm_connector,
-			     hdmi_hpd_debounce_work);
-	struct drm_connector *connector = &aconnector->base;
-	struct drm_device *dev = connector->dev;
-	struct amdgpu_device *adev = drm_to_adev(dev);
-	struct dc *dc = aconnector->dc_link->ctx->dc;
-	bool fake_reconnect = false;
-	bool reallow_idle = false;
-	bool ret = false;
-	guard(mutex)(&aconnector->hpd_lock);
-
-	/* Re-detect the display */
-	scoped_guard(mutex, &adev->dm.dc_lock) {
-		if (dc->caps.ips_support && dc->ctx->dmub_srv->idle_allowed) {
-			dc_allow_idle_optimizations(dc, false);
-			reallow_idle = true;
-		}
-		ret = dc_link_detect(aconnector->dc_link, DETECT_REASON_HPD);
-	}
-
-	if (ret) {
-		/* Apply workaround delay for certain panels */
-		apply_delay_after_dpcd_poweroff(adev, aconnector->dc_sink);
-		/* Compare sinks to determine if this was a spontaneous HPD toggle */
-		if (are_sinks_equal(aconnector->dc_link->local_sink, aconnector->hdmi_prev_sink)) {
-			/*
-			* Sinks match - this was a spontaneous HDMI HPD toggle.
-			*/
-			drm_dbg_kms(dev, "HDMI HPD: Sink unchanged after debounce, internal re-enable\n");
-			fake_reconnect = true;
-		}
-
-		/* Update connector state */
-		amdgpu_dm_update_connector_after_detect(aconnector);
-
-		drm_modeset_lock_all(dev);
-		dm_restore_drm_connector_state(dev, connector);
-		drm_modeset_unlock_all(dev);
-
-		/* Only notify OS if sink actually changed */
-		if (!fake_reconnect && aconnector->base.force == DRM_FORCE_UNSPECIFIED)
-			drm_kms_helper_hotplug_event(dev);
-	}
-
-	/* Release the cached sink reference */
-	if (aconnector->hdmi_prev_sink) {
-		dc_sink_release(aconnector->hdmi_prev_sink);
-		aconnector->hdmi_prev_sink = NULL;
-	}
-
-	scoped_guard(mutex, &adev->dm.dc_lock) {
-		if (reallow_idle && dc->caps.ips_support)
-			dc_allow_idle_optimizations(dc, true);
-	}
-}
-
-static bool are_sinks_equal(const struct dc_sink *sink1, const struct dc_sink *sink2)
-{
-	if (!sink1 || !sink2)
-		return false;
-	if (sink1->sink_signal != sink2->sink_signal)
-		return false;
-
-	if (sink1->dc_edid.length != sink2->dc_edid.length)
-		return false;
-
-	if (memcmp(sink1->dc_edid.raw_edid, sink2->dc_edid.raw_edid,
-		   sink1->dc_edid.length) != 0)
-		return false;
-	return true;
-}
-
-
 /**
  * DOC: hdmi_hpd_debounce_work
  *
-- 
2.52.0

-- 
Cheers,
Stephen Rothwell