drm/i915/dp: Ensure panel power remains enabled during connector detection

The sink's capabilities, like the DSC caps, depend on the source OUI
written to the sink's DPCD registers and so this OUI value should be
valid for the whole duration of the detection. An eDP sink will reset
this OUI value when the panel power is disabled, so prevent the
disabling - happening by default after a 1 sec idle period - for the
whole duration of detection.

v2: Update the documentation for intel_pps_on(). (Jani)

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241025160259.3088727-3-imre.deak@intel.com

1 files changed, 13 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/display/intel_pps.c b/drivers/gpu/drm/i915/display/intel_pps.c
index 0bd8e4de8b69..a1b2c400d6a5 100644
--- a/drivers/gpu/drm/i915/display/intel_pps.c
+++ b/drivers/gpu/drm/i915/display/intel_pps.c
@@ -797,7 +797,8 @@ bool intel_pps_vdd_on_unlocked(struct intel_dp *intel_dp)
 }
 
 /*
- * Must be paired with intel_pps_off().
+ * Must be paired with intel_pps_vdd_off() or - to disable
+ * both VDD and panel power - intel_pps_off().
  * Nested calls to these functions are not allowed since
  * we drop the lock. Caller must use some higher level
  * locking to prevent nested calls from other threads.
@@ -944,6 +945,17 @@ void intel_pps_vdd_off_unlocked(struct intel_dp *intel_dp, bool sync)
 		edp_panel_vdd_schedule_off(intel_dp);
 }
 
+void intel_pps_vdd_off(struct intel_dp *intel_dp)
+{
+	intel_wakeref_t wakeref;
+
+	if (!intel_dp_is_edp(intel_dp))
+		return;
+
+	with_intel_pps_lock(intel_dp, wakeref)
+		intel_pps_vdd_off_unlocked(intel_dp, false);
+}
+
 void intel_pps_on_unlocked(struct intel_dp *intel_dp)
 {
 	struct intel_display *display = to_intel_display(intel_dp);