[PATCH] drm/amd/display: Fix deadlock during gpu reset v3

[Bhawanpreet Lakha]

[Why]
during idle optimizations we acquire the dc_lock, this lock is also
acquired during gpu_reset so we end up hanging the system due to a
deadlock

[How]
If we are in gpu reset:
 - disable idle optimizations and skip calls to the dc function

v2: skip idle optimizations calls
v3: add guard for DCN

Fixes: 06d5652541c3 ("drm/amd/display: enable idle optimizations for linux (MALL stutter)")
Signed-off-by: Bhawanpreet Lakha <Bhawanpreet.Lakha at amd.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 10 ++++++++++
 1 file changed, 10 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 de71b6c21590..82ceb0a8ba29 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -1816,6 +1816,11 @@ static int dm_suspend(void *handle)
 
 	if (amdgpu_in_reset(adev)) {
 		mutex_lock(&dm->dc_lock);
+
+#if defined(CONFIG_DRM_AMD_DC_DCN)
+		dc_allow_idle_optimizations(adev->dm.dc, false);
+#endif
+
 		dm->cached_dc_state = dc_copy_state(dm->dc->current_state);
 
 		dm_gpureset_toggle_interrupts(adev, dm->cached_dc_state, false);
@@ -5556,6 +5561,10 @@ static inline int dm_set_vblank(struct drm_crtc *crtc, bool enable)
 	if (!dc_interrupt_set(adev->dm.dc, irq_source, enable))
 		return -EBUSY;
 
+#if defined(CONFIG_DRM_AMD_DC_DCN)
+	if (amdgpu_in_reset(adev))
+		return 0;
+
 	mutex_lock(&dm->dc_lock);
 
 	if (enable)
@@ -5572,6 +5581,7 @@ static inline int dm_set_vblank(struct drm_crtc *crtc, bool enable)
 
 	mutex_unlock(&dm->dc_lock);
 
+#endif
 	return 0;
 }
 
-- 
2.25.1