unimore/kernel-hacking-2024-linux-steffo
unimore/kernel-hacking-2024-linux-steffo
1
Fork 0
Code Pull requests 5 Wiki Activity

drm/i915: fixup forcewake spinlock fallout in drpc debugfs function

Browse source 
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>
This commit is contained in:
Daniel Vetter 2012-01-25 13:52:43 +01:00 committed by Keith Packard
parent 48467a9221
commit 93b525dccf
1 changed files with 8 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

11
drivers/gpu/drm/i915/i915_debugfs.c
View file

@ -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))