drm/radeon: avoid deadlock in pm path when waiting for fence

radeon_fence_wait_empty_locked should not trigger GPU reset as no
place where it's call from would benefit from such thing and it
actually lead to a kernel deadlock in case the reset is triggered
from pm codepath. Instead force ring completion in place where it
makes sense or return early in others.

Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

1 files changed, 11 insertions, 2 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
index e81d6cab9959..a6617b53a9c6 100644
--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -1164,6 +1164,7 @@ int radeon_suspend_kms(struct drm_device *dev, pm_message_t state)
         struct drm_crtc *crtc;
         struct drm_connector *connector;
         int i, r;
+        bool force_completion = false;
 
         if (dev == NULL || dev->dev_private == NULL) {
                 return -ENODEV;
@@ -1206,8 +1207,16 @@ int radeon_suspend_kms(struct drm_device *dev, pm_message_t state)
 
         mutex_lock(&rdev->ring_lock);
         /* wait for gpu to finish processing current batch */
-        for (i = 0; i < RADEON_NUM_RINGS; i++)
-                radeon_fence_wait_empty_locked(rdev, i);
+        for (i = 0; i < RADEON_NUM_RINGS; i++) {
+                r = radeon_fence_wait_empty_locked(rdev, i);
+                if (r) {
+                        /* delay GPU reset to resume */
+                        force_completion = true;
+                }
+        }
+        if (force_completion) {
+                radeon_fence_driver_force_completion(rdev);
+        }
         mutex_unlock(&rdev->ring_lock);
 
         radeon_save_bios_scratch_regs(rdev);