When the DMC wakelock refcount reaches zero, we know that there are no
users and that we can do the actual release operation on the hardware,
which is queued with a delayed work. The idea of the delayed work is to
avoid performing the release if a new lock user appears (i.e. refcount
gets incremented) in a very short period of time.
Based on the above, the release work should bail out if refcount is
non-zero (meaning new lock users appeared in the meantime), but our
current code actually does the opposite: it bails when refcount is zero.
That means that the wakelock is not released when it should be; and
that, when the work is not canceled in time, it ends up being releasing
when it should not.
Fix that by inverting the condition.
Signed-off-by: Gustavo Sousa <gustavo.so...@intel.com>
---
drivers/gpu/drm/i915/display/intel_dmc_wl.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_dmc_wl.c
b/drivers/gpu/drm/i915/display/intel_dmc_wl.c
index 8056a3c8666c..c298aef89449 100644
--- a/drivers/gpu/drm/i915/display/intel_dmc_wl.c
+++ b/drivers/gpu/drm/i915/display/intel_dmc_wl.c
@@ -72,8 +72,11 @@ static void intel_dmc_wl_work(struct work_struct *work)
spin_lock_irqsave(&wl->lock, flags);
- /* Bail out if refcount reached zero while waiting for the spinlock */
- if (!refcount_read(&wl->refcount))
+ /*
+ * Bail out if refcount became non-zero while waiting for the spinlock,
+ * meaning that the lock is now taken again.
+ */
+ if (refcount_read(&wl->refcount))
goto out_unlock;
__intel_de_rmw_nowl(display, DMC_WAKELOCK1_CTL, DMC_WAKELOCK_CTL_REQ,
0);
--
2.47.0
