From 93b525dccf212e50a895792d79d64bdb53312f5c Mon Sep 17 00:00:00 2001 From: Daniel Vetter 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 Reviewed-by: Ben Widawsky Signed-off-by: Keith Packard --- 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)) -- 2.30.2