[PATCH 1/1][SRU][N][O] UBUNTU: SAUCE: drm/amd/display: Fix system hang while resume with TBT monitor

[Chia-Lin Kao (AceLan)]

From: Tom Chung <chiahsuan.chung at amd.com>

BugLink: https://bugs.launchpad.net/bugs/2083182

[Why]
Connected with a Thunderbolt monitor and do the suspend and the system
may hang while resume.

The TBT monitor HPD will be triggered during the resume procedure
and call the drm_client_modeset_probe() while
struct drm_connector connector->dev->master is NULL.

It will mess up the pipe topology after resume.

[How]
Skip the TBT monitor HPD during the resume procedure because we
currently will probe the connectors after resume by default.

Reviewed-by: Wayne Lin <wayne.lin at amd.com>
Signed-off-by: Tom Chung <chiahsuan.chung at amd.com>
Signed-off-by: Fangzhi Zuo <jerry.zuo at amd.com>
(cherry picked from commit https://lore.kernel.org/all/20240927170103.102180-3-Jerry.Zuo@amd.com/T/#e868f6b967ec79ae85c5a8a446be9b5d5c97e5427)
Signed-off-by: Chia-Lin Kao (AceLan) <acelan.kao at canonical.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 6 ++++++
 1 file changed, 6 insertions(+)

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 a830b74cf4cb..6471448506df 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -756,6 +756,12 @@ static void dmub_hpd_callback(struct amdgpu_device *adev,
 		return;
 	}
 
+	/* Skip DMUB HPD IRQ in suspend/resume. We will probe them later. */
+	if (notify->type == DMUB_NOTIFICATION_HPD && adev->in_suspend) {
+		DRM_INFO("Skip DMUB HPD IRQ callback in suspend/resume\n");
+		return;
+	}
+
 	link_index = notify->link_index;
 	link = adev->dm.dc->links[link_index];
 	dev = adev->dm.ddev;
-- 
2.43.0