From: Roman Li <Roman.Li@amd.com>
Date: Mon, 19 Apr 2021 15:47:00 +0000 (-0400)
Subject: drm/amd/display: fix potential gpu reset deadlock
X-Git-Tag: Ubuntu-5.11.0-34.36~51
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=9e33a51a5191c982b25ace2a8fa1234fb9a63398;p=mirror_ubuntu-hirsute-kernel.git

drm/amd/display: fix potential gpu reset deadlock

BugLink: https://bugs.launchpad.net/bugs/1938340

[ Upstream commit cf8b92a75646735136053ce51107bfa8cfc23191 ]

[Why]
In gpu reset dc_lock acquired in dm_suspend().
Asynchronously handle_hpd_rx_irq can also be called
through amdgpu_dm_irq_suspend->flush_work, which also
tries to acquire dc_lock. That causes a deadlock.

[How]
Check if amdgpu executing reset before acquiring dc_lock.

Signed-off-by: Lang Yu <Lang.Yu@amd.com>
Signed-off-by: Roman Li <Roman.Li@amd.com>
Reviewed-by: Qingqing Zhuo <Qingqing.Zhuo@amd.com>
Acked-by: Wayne Lin <Wayne.Lin@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
---

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 35dd8f9f703e..3031f31415a1 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -2557,13 +2557,15 @@ static void handle_hpd_rx_irq(void *param)
 		}
 	}
 
-	mutex_lock(&adev->dm.dc_lock);
+	if (!amdgpu_in_reset(adev))
+		mutex_lock(&adev->dm.dc_lock);
 #ifdef CONFIG_DRM_AMD_DC_HDCP
 	result = dc_link_handle_hpd_rx_irq(dc_link, &hpd_irq_data, NULL);
 #else
 	result = dc_link_handle_hpd_rx_irq(dc_link, NULL, NULL);
 #endif
-	mutex_unlock(&adev->dm.dc_lock);
+	if (!amdgpu_in_reset(adev))
+		mutex_unlock(&adev->dm.dc_lock);
 
 out:
 	if (result && !is_mst_root_connector) {