[Intel-gfx] [PATCH] drm/i915/pps: Reuse POWER_DOMAIN_DISPLAY_CORE in pps_{lock, unlock}

Anshuman Gupta anshuman.gupta at intel.com
Thu Jan 7 11:23:01 UTC 2021

We need a power_domain wakeref in pps_{lock,unlock} to prevent
a race while resetting pps state in intel_power_sequencer_reset().

intel_power_sequencer_reset() need a pps_mutex to access pps_pipe
but it can't grab pps_mutex due to deadlock with power_well
functions are called while holding pps_mutex.
intel_power_sequencer_reset() is called by power_well function
associated with legacy platforms like vlv and chv therefore re-use
the POWER_DOMAIN_DISPLAY_CORE power domain, which only used
by vlv and chv display power domain.

This will avoids the unnecessary noise of unrelated power wells
in pps_{lock,unlock}.

Cc: Jani Nikula <jani.nikula at intel.com>
Cc: Imre Deak <imre.deak at intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta at intel.com>
 drivers/gpu/drm/i915/display/intel_dp.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 8a00e609085f..4f190a82d4ad 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -895,9 +895,7 @@ pps_lock(struct intel_dp *intel_dp)
 	 * See intel_power_sequencer_reset() why we need
 	 * a power domain reference here.
-	wakeref = intel_display_power_get(dev_priv,
-					  intel_aux_power_domain(dp_to_dig_port(intel_dp)));
+	wakeref = intel_display_power_get(dev_priv, POWER_DOMAIN_DISPLAY_CORE);
 	return wakeref;
@@ -909,9 +907,7 @@ pps_unlock(struct intel_dp *intel_dp, intel_wakeref_t wakeref)
 	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
-	intel_display_power_put(dev_priv,
-				intel_aux_power_domain(dp_to_dig_port(intel_dp)),
-				wakeref);
+	intel_display_power_put(dev_priv, POWER_DOMAIN_DISPLAY_CORE, wakeref);
 	return 0;

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