[Intel-gfx] [PATCH] drm/i915: fix locking around punit access in cur_delayinfo for VLV

[Jesse Barnes]

We need to hold the rps lock around punit access.

Reported-by: Kenneth Graunke <kenneth at whitecape.org>
Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>
---
 drivers/gpu/drm/i915/i915_debugfs.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 367b534..d195d09 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -1012,6 +1012,7 @@ static int i915_cur_delayinfo(struct seq_file *m, void *unused)
 	} else if (IS_VALLEYVIEW(dev)) {
 		u32 freq_sts, val;
 
+		mutex_lock(&dev_priv->rps.hw_lock);
 		valleyview_punit_read(dev_priv, PUNIT_REG_GPU_FREQ_STS,
 				      &freq_sts);
 		seq_printf(m, "PUNIT_REG_GPU_FREQ_STS: 0x%08x\n", freq_sts);
@@ -1028,6 +1029,7 @@ static int i915_cur_delayinfo(struct seq_file *m, void *unused)
 		seq_printf(m, "current GPU freq: %d MHz\n",
 			   vlv_gpu_freq(dev_priv->mem_freq,
 					(freq_sts >> 8) & 0xff));
+		mutex_unlock(&dev_priv->rps.hw_lock);
 	} else {
 		seq_printf(m, "no P-state info available\n");
 	}
-- 
1.7.10.4