From 93b525dccf212e50a895792d79d64bdb53312f5c Mon Sep 17 00:00:00 2001
From: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Wed, 25 Jan 2012 13:52:43 +0100
Subject: [PATCH] drm/i915: fixup forcewake spinlock fallout in drpc debugfs
function
My forcewake spinlock patches have a functional conflict with Ben
Widawsky's gen6 drpc support for debugfs. Result was a benign warning
about trying to read an non-atomic variabla with atomic_read.
Note that the entire check is racy anyway and purely informational.
Also update it to reflect the forcewake voodoo changes, the kernel can
now also hold onto a forcewake reference for longer times.
Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Keith Packard <keithp@keithp.com>
---
drivers/gpu/drm/i915/i915_debugfs.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 99f140798808..deaa657292b4 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -1075,6 +1075,7 @@ static int gen6_drpc_info(struct seq_file *m)
struct drm_device *dev = node->minor->dev;
struct drm_i915_private *dev_priv = dev->dev_private;
u32 rpmodectl1, gt_core_status, rcctl1;
+ unsigned forcewake_count;
int count=0, ret;
@@ -1082,9 +1083,13 @@ static int gen6_drpc_info(struct seq_file *m)
if (ret)
return ret;
- if (atomic_read(&dev_priv->forcewake_count)) {
- seq_printf(m, "RC information inaccurate because userspace "
- "holds a reference \n");
+ spin_lock_irq(&dev_priv->gt_lock);
+ forcewake_count = dev_priv->forcewake_count;
+ spin_unlock_irq(&dev_priv->gt_lock);
+
+ if (forcewake_count) {
+ seq_printf(m, "RC information inaccurate because somebody "
+ "holds a forcewake reference \n");
} else {
/* NB: we cannot use forcewake, else we read the wrong values */
while (count++ < 50 && (I915_READ_NOTRACE(FORCEWAKE_ACK) & 1))
--
2.34.1