From e393d0d6c12527b2bd7faf0b5ca7edde2543c451 Mon Sep 17 00:00:00 2001 From: Imre Deak Date: Wed, 22 Feb 2017 17:10:52 +0200 Subject: [PATCH] drm/i915/lspcon: Switch back to PCON mode after output replug MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit At least a ParadTech PS175 LSPCON chip/firmware uses long instead of short pulses to signal output unplug/plug events. This is contrary to how branch devices normally work which use short HPD signaling. This chip will also switch to LS mode after an unplug event, which could be the consequence of the long HPD signaling semantics and an effort to save power automatically. Because of this we'll fail to do AUX and detect the output after a replug event. To fix this make sure we are in PCON mode during connector detection. v2: - Switch the mode in the proper spot. Cc: raptorteak@gmail.com Cc: Shashank Sharma Cc: Ville Syrjälä Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=98912 Reported-and-tested-by: raptorteak@gmail.com Signed-off-by: Imre Deak Reviewed-by: Ville Syrjälä Link: http://patchwork.freedesktop.org/patch/msgid/1487776252-6288-1-git-send-email-imre.deak@intel.com --- drivers/gpu/drm/i915/intel_dp.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index e72c92a08c81..6c661c64cff6 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -4325,9 +4325,13 @@ intel_dp_short_pulse(struct intel_dp *intel_dp) static enum drm_connector_status intel_dp_detect_dpcd(struct intel_dp *intel_dp) { + struct intel_lspcon *lspcon = dp_to_lspcon(intel_dp); uint8_t *dpcd = intel_dp->dpcd; uint8_t type; + if (lspcon->active) + lspcon_resume(lspcon); + if (!intel_dp_get_dpcd(intel_dp)) return connector_status_disconnected; -- 2.20.1