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| author | Daniel Vetter <daniel.vetter@ffwll.ch> | 2012-01-25 13:52:43 +0100 |
|---|---|---|
| committer | Keith Packard <keithp@keithp.com> | 2012-01-25 09:15:33 -0800 |
| commit | 93b525dccf212e50a895792d79d64bdb53312f5c (patch) | |
| tree | 8fa3fb39990b700709bb9480890eea8f6571f744 /drivers/gpu/drm/i915/i915_debugfs.c | |
| parent | 48467a92215ced69a65c89c1b064dd84728a5ed0 (diff) | |
| download | lwn-93b525dccf212e50a895792d79d64bdb53312f5c.tar.gz lwn-93b525dccf212e50a895792d79d64bdb53312f5c.zip | |
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>
Diffstat (limited to 'drivers/gpu/drm/i915/i915_debugfs.c')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_debugfs.c | 11 |
1 files 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)) |