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drm/i915/dmc_wl: Check for non-zero refcount in release work

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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.

Reviewed-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Gustavo Sousa <gustavo.sousa@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241108130218.24125-5-gustavo.sousa@intel.com
This commit is contained in:
Gustavo Sousa
2024-11-08 09:57:09 -03:00
committed by Matt Roper
parent b2ba4632b9
commit f7b12bf296
1 changed files with 5 additions and 2 deletions
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7
drivers/gpu/drm/i915/display/intel_dmc_wl.c
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@@ -76,8 +76,11 @@ 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);