lock must be held for GT register reads.
Uncovered with intel-gpu-dump.
Cc: [email protected]
Reported-by: [email protected]
Signed-off-by: Ben Widawsky <[email protected]>
---
drivers/gpu/drm/i915/i915_debugfs.c | 6 ++++++
1 files changed, 6 insertions(+), 0 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c
b/drivers/gpu/drm/i915/i915_debugfs.c
index 51c2257..d5b79e5 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -635,11 +635,16 @@ static int i915_ringbuffer_info(struct seq_file *m, void
*data)
struct drm_device *dev = node->minor->dev;
drm_i915_private_t *dev_priv = dev->dev_private;
struct intel_ring_buffer *ring;
+ int ret;
ring = &dev_priv->ring[(uintptr_t)node->info_ent->data];
if (ring->size == 0)
return 0;
+ ret = mutex_lock_interruptible(&dev->struct_mutex);
+ if (ret)
+ return ret;
+
seq_printf(m, "Ring %s:\n", ring->name);
seq_printf(m, " Head : %08x\n", I915_READ_HEAD(ring) & HEAD_ADDR);
seq_printf(m, " Tail : %08x\n", I915_READ_TAIL(ring) & TAIL_ADDR);
@@ -652,6 +657,7 @@ static int i915_ringbuffer_info(struct seq_file *m, void
*data)
}
seq_printf(m, " Control : %08x\n", I915_READ_CTL(ring));
seq_printf(m, " Start : %08x\n", I915_READ_START(ring));
+ mutex_unlock(&dev->struct_mutex);
return 0;
}
--
1.7.3.4
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