drm/amd/display: Fix system hang after multiple hotplugs (v3)

[Why]
mutex_lock() was introduced in dm_disable_vblank(), which could
be called in an IRQ context. Waiting in IRQ would cause issues
like kernel lockup, etc.

[How]
Handle code that requires mutex lock on a different thread.

v2: squash in compilation fix without CONFIG_DRM_AMD_DC_DCN (Alex)
v3: squash in warning fix (Wei)

Signed-off-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Acked-by: Bindu Ramamurthy <bindu.r@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

1 files changed, 27 insertions, 0 deletions

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
index 0bb974ca89ed..bbf68cb6cfec 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
@@ -93,6 +93,20 @@ struct dm_compressor_info {
 };
 
 /**
+ * struct vblank_workqueue - Works to be executed in a separate thread during vblank
+ * @mall_work: work for mall stutter
+ * @dm: amdgpu display manager device
+ * @otg_inst: otg instance of which vblank is being set
+ * @enable: true if enable vblank
+ */
+struct vblank_workqueue {
+	struct work_struct mall_work;
+	struct amdgpu_display_manager *dm;
+	int otg_inst;
+	bool enable;
+};
+
+/**
  * struct amdgpu_dm_backlight_caps - Information about backlight
  *
  * Describe the backlight support for ACPI or eDP AUX.
@@ -244,6 +258,15 @@ struct amdgpu_display_manager {
 	struct mutex audio_lock;
 
 	/**
+	 * @vblank_work_lock:
+	 *
+	 * Guards access to deferred vblank work state.
+	 */
+#if defined(CONFIG_DRM_AMD_DC_DCN)
+	spinlock_t vblank_lock;
+#endif
+
+	/**
 	 * @audio_component:
 	 *
 	 * Used to notify ELD changes to sound driver.
@@ -321,6 +344,10 @@ struct amdgpu_display_manager {
 	struct hdcp_workqueue *hdcp_workqueue;
 #endif
 
+#if defined(CONFIG_DRM_AMD_DC_DCN)
+	struct vblank_workqueue *vblank_workqueue;
+#endif
+
 	struct drm_atomic_state *cached_state;
 	struct dc_state *cached_dc_state;