drm/i915: Take runtime pm reference on hangcheck_info

We read the coherent current seqno and actual head from ring.
For hardware access we need to take runtime_pm reference.

Get hardware specific values with runtime reference held
and print them first to emphasize hw state vs bookkeepping.

v2: Reorder output according to hw access (Chris)
    remove superfluous locking (Daniel)

Testcase: igt/pm_rpm/debugfs-read
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=88910
Tested-by: Ding Heng <hengx.ding@intel.com> (v1)
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

1 files changed, 17 insertions, 5 deletions

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 211d4949a675..96e811fe24ca 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -1223,8 +1223,11 @@ out:
 static int i915_hangcheck_info(struct seq_file *m, void *unused)
 {
         struct drm_info_node *node = m->private;
-        struct drm_i915_private *dev_priv = to_i915(node->minor->dev);
+        struct drm_device *dev = node->minor->dev;
+        struct drm_i915_private *dev_priv = dev->dev_private;
         struct intel_engine_cs *ring;
+        u64 acthd[I915_NUM_RINGS];
+        u32 seqno[I915_NUM_RINGS];
         int i;
 
         if (!i915.enable_hangcheck) {
@@ -1232,6 +1235,15 @@ static int i915_hangcheck_info(struct seq_file *m, void *unused)
                 return 0;
         }
 
+        intel_runtime_pm_get(dev_priv);
+
+        for_each_ring(ring, dev_priv, i) {
+                seqno[i] = ring->get_seqno(ring, false);
+                acthd[i] = intel_ring_get_active_head(ring);
+        }
+
+        intel_runtime_pm_put(dev_priv);
+
         if (delayed_work_pending(&dev_priv->gpu_error.hangcheck_work)) {
                 seq_printf(m, "Hangcheck active, fires in %dms\n",
                            jiffies_to_msecs(dev_priv->gpu_error.hangcheck_work.timer.expires -
@@ -1242,14 +1254,14 @@ static int i915_hangcheck_info(struct seq_file *m, void *unused)
         for_each_ring(ring, dev_priv, i) {
                 seq_printf(m, "%s:\n", ring->name);
                 seq_printf(m, "\tseqno = %x [current %x]\n",
-                           ring->hangcheck.seqno, ring->get_seqno(ring, false));
-                seq_printf(m, "\taction = %d\n", ring->hangcheck.action);
-                seq_printf(m, "\tscore = %d\n", ring->hangcheck.score);
+                           ring->hangcheck.seqno, seqno[i]);
                 seq_printf(m, "\tACTHD = 0x%08llx [current 0x%08llx]\n",
                            (long long)ring->hangcheck.acthd,
-                           (long long)intel_ring_get_active_head(ring));
+                           (long long)acthd[i]);
                 seq_printf(m, "\tmax ACTHD = 0x%08llx\n",
                            (long long)ring->hangcheck.max_acthd);
+                seq_printf(m, "\tscore = %d\n", ring->hangcheck.score);
+                seq_printf(m, "\taction = %d\n", ring->hangcheck.action);
         }
 
         return 0;