linux-kernel - [PATCH] drm/amd/display: fix issues with driver unload

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Message-ID: <20230117205452.195298-1-hamza.mahfooz@amd.com>
Date:   Tue, 17 Jan 2023 15:54:51 -0500
From:   Hamza Mahfooz <hamza.mahfooz@....com>
To:     <amd-gfx@...ts.freedesktop.org>
CC:     Hamza Mahfooz <hamza.mahfooz@....com>,
        Harry Wentland <harry.wentland@....com>,
        Leo Li <sunpeng.li@....com>,
        Rodrigo Siqueira <Rodrigo.Siqueira@....com>,
        Alex Deucher <alexander.deucher@....com>,
        Christian König <christian.koenig@....com>,
        "Pan, Xinhui" <Xinhui.Pan@....com>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>, Wayne Lin <Wayne.Lin@....com>,
        Roman Li <roman.li@....com>,
        Aurabindo Pillai <aurabindo.pillai@....com>,
        hersen wu <hersenxs.wu@....com>,
        Fangzhi Zuo <Jerry.Zuo@....com>, Lyude Paul <lyude@...hat.com>,
        Nicholas Kazlauskas <nicholas.kazlauskas@....com>,
        <dri-devel@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH] drm/amd/display: fix issues with driver unload

Currently, we run into a number of WARN()s when attempting to unload the
amdgpu driver (e.g. using "modprobe -r amdgpu"). These all stem from
calling drm_encoder_cleanup() too early. So, to fix this we can stop
calling drm_encoder_cleanup() in amdgpu_dm_fini() and instead have it be
called from amdgpu_dm_encoder_destroy(). Also, we don't need to free in
amdgpu_dm_encoder_destroy() since mst_encoders[] isn't explicitly
allocated by the slab allocater.

Fixes: f74367e492ba ("drm/amdgpu/display: create fake mst encoders ahead of time (v4)")
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@....com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c           | 4 ----
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c | 1 -
 2 files changed, 5 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 9547037857b6..5cc14ed2e93e 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -1733,10 +1733,6 @@ static void amdgpu_dm_fini(struct amdgpu_device *adev)
 		adev->dm.vblank_control_workqueue = NULL;
 	}
 
-	for (i = 0; i < adev->dm.display_indexes_num; i++) {
-		drm_encoder_cleanup(&adev->dm.mst_encoders[i].base);
-	}
-
 	amdgpu_dm_destroy_drm_device(&adev->dm);
 
 #if defined(CONFIG_DRM_AMD_SECURE_DISPLAY)
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
index bbeeee7c5d7c..5fa9bab95038 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
@@ -492,7 +492,6 @@ static const struct drm_connector_helper_funcs dm_dp_mst_connector_helper_funcs
 static void amdgpu_dm_encoder_destroy(struct drm_encoder *encoder)
 {
 	drm_encoder_cleanup(encoder);
-	kfree(encoder);
 }
 
 static const struct drm_encoder_funcs amdgpu_dm_encoder_funcs = {
-- 
2.39.0