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. Cc: raptorteak@xxxxxxxxx Cc: Shashank Sharma <shashank.sharma@xxxxxxxxx> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=98912 Reported-and-tested-by: raptorteak@xxxxxxxxx Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx> --- 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 024798a..2a3ec20 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -4270,12 +4270,16 @@ intel_dp_check_link_status(struct intel_dp *intel_dp) static bool intel_dp_short_pulse(struct intel_dp *intel_dp) { + struct intel_lspcon *lspcon = dp_to_lspcon(intel_dp); struct drm_device *dev = intel_dp_to_dev(intel_dp); struct intel_encoder *intel_encoder = &dp_to_dig_port(intel_dp)->base; u8 sink_irq_vector = 0; u8 old_sink_count = intel_dp->sink_count; bool ret; + if (lspcon->active) + lspcon_resume(lspcon); + /* * Clearing compliance test variables to allow capturing * of values for next automated test request. -- 2.5.0 _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
