According to BSPec:
Sequence to Allow DC9:
1. Follow Sequence to Disallow DC5.
which is:
Sequence to Disallow DC5 and DC6
Set DC_STATE_EN Dynamic DC State Enable = "Disable".
I understand that we haven't had any issue so far. But since
DC9 is a software thing, it is better to disable DC5 before
to avoid any conflict. And respect the spec to avoid potential
future issues.
Cc: Imre Deak <imre.deak@xxxxxxxxx>
Cc: Anshuman Gupta <anshuman.gupta@xxxxxxxxx>
Cc: Anusha Srivatsa <anusha.srivatsa@xxxxxxxxx>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_display_power.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/gpu/drm/i915/display/intel_display_power.c b/drivers/gpu/drm/i915/display/intel_display_power.c
index 6a5695008f7c..b3cf5182044f 100644
--- a/drivers/gpu/drm/i915/display/intel_display_power.c
+++ b/drivers/gpu/drm/i915/display/intel_display_power.c
@@ -883,6 +883,9 @@ static void bxt_enable_dc9(struct drm_i915_private *dev_priv)
{
assert_can_enable_dc9(dev_priv);
+ /* Disable DC5 before enabling DC9 */
+ gen9_set_dc_state(dev_priv, DC_STATE_DISABLE);
+
drm_dbg_kms(&dev_priv->drm, "Enabling DC9\n");
/*
* Power sequencer reset is not needed on
--
2.34.1
