Merge tag 'drm-fixes-for-v4.13-rc2' of git://people.freedesktop.org/~airlied/linux

Pull drm fixes from Dave Airlie:
 "A bunch of fixes for rc2: two imx regressions, vc4 fix, dma-buf fix,
  some displayport mst fixes, and an amdkfd fix.

  Nothing too crazy, I assume we just haven't see much rc1 testing yet"

* tag 'drm-fixes-for-v4.13-rc2' of git://people.freedesktop.org/~airlied/linux:
  drm/mst: Avoid processing partially received up/down message transactions
  drm/mst: Avoid dereferencing a NULL mstb in drm_dp_mst_handle_up_req()
  drm/mst: Fix error handling during MST sideband message reception
  drm/imx: parallel-display: Accept drm_of_find_panel_or_bridge failure
  drm/imx: fix typo in ipu_plane_formats[]
  drm/vc4: Fix VBLANK handling in crtc->enable() path
  dma-buf/fence: Avoid use of uninitialised timestamp
  drm/amdgpu: Remove unused field kgd2kfd_shared_resources.num_mec
  drm/radeon: Remove initialization of shared_resources.num_mec
  drm/amdkfd: Remove unused references to shared_resources.num_mec
  drm/amdgpu: Fix KFD oversubscription by tracking queues correctly

3 files changed, 14 insertions, 13 deletions

diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
index 57da14c15987..56e0a0e1b600 100644
--- a/drivers/dma-buf/dma-fence.c
+++ b/drivers/dma-buf/dma-fence.c
@@ -75,11 +75,6 @@ int dma_fence_signal_locked(struct dma_fence *fence)
         if (WARN_ON(!fence))
                 return -EINVAL;
 
-        if (!ktime_to_ns(fence->timestamp)) {
-                fence->timestamp = ktime_get();
-                smp_mb__before_atomic();
-        }
-
         if (test_and_set_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) {
                 ret = -EINVAL;
 
@@ -87,8 +82,11 @@ int dma_fence_signal_locked(struct dma_fence *fence)
                  * we might have raced with the unlocked dma_fence_signal,
                  * still run through all callbacks
                  */
-        } else
+        } else {
+                fence->timestamp = ktime_get();
+                set_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags);
                 trace_dma_fence_signaled(fence);
+        }
 
         list_for_each_entry_safe(cur, tmp, &fence->cb_list, node) {
                 list_del_init(&cur->node);
@@ -115,14 +113,11 @@ int dma_fence_signal(struct dma_fence *fence)
         if (!fence)
                 return -EINVAL;
 
-        if (!ktime_to_ns(fence->timestamp)) {
-                fence->timestamp = ktime_get();
-                smp_mb__before_atomic();
-        }
-
         if (test_and_set_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
                 return -EINVAL;
 
+        fence->timestamp = ktime_get();
+        set_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags);
         trace_dma_fence_signaled(fence);
 
         if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &fence->flags)) {
diff --git a/drivers/dma-buf/sync_debug.c b/drivers/dma-buf/sync_debug.c
index 82a6e7f6d37f..59a3b2f8ee91 100644
--- a/drivers/dma-buf/sync_debug.c
+++ b/drivers/dma-buf/sync_debug.c
@@ -84,7 +84,7 @@ static void sync_print_fence(struct seq_file *s,
                    show ? "_" : "",
                    sync_status_str(status));
 
-        if (status) {
+        if (test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags)) {
                 struct timespec64 ts64 =
                         ktime_to_timespec64(fence->timestamp);
 
diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c
index 545e2c5c4815..d7e219d2669d 100644
--- a/drivers/dma-buf/sync_file.c
+++ b/drivers/dma-buf/sync_file.c
@@ -391,7 +391,13 @@ static void sync_fill_fence_info(struct dma_fence *fence,
                 sizeof(info->driver_name));
 
         info->status = dma_fence_get_status(fence);
-        info->timestamp_ns = ktime_to_ns(fence->timestamp);
+        while (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags) &&
+               !test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags))
+                cpu_relax();
+        info->timestamp_ns =
+                test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags) ?
+                ktime_to_ns(fence->timestamp) :
+                ktime_set(0, 0);
 }
 
 static long sync_file_ioctl_fence_info(struct sync_file *sync_file,