drm/i915/dp: there is no audio on port A

The eDP port A register on PCH split platforms has a slightly different
register layout from the other ports, with bit 6 being either alternate
scrambler reset or reserved, depending on the generation. Our
misinterpretation of the bit as audio has lead to warning.

Fix this by not enabling audio on port A, since none of our platforms
support audio on port A anyway.

v2: DDI doesn't have audio on port A either (Sivakumar Thulasimani)

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=89958
Reported-and-tested-by: Chris Bainbridge <chris.bainbridge@gmail.com>
Cc: stable@vger.kernel.org
Reviewed-by: Sivakumar Thulasimani <sivakumar.thulasimani@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index d0237102c27ecf1323e39ee1d67cee07e3760f60..8d534f409b2394c0c7753d78922da803ee4fdaa8 100644 (file)
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1348,7 +1348,7 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 
        pipe_config->has_dp_encoder = true;
        pipe_config->has_drrs = false;
-       pipe_config->has_audio = intel_dp->has_audio;
+       pipe_config->has_audio = intel_dp->has_audio && port != PORT_A;
 
        if (is_edp(intel_dp) && intel_connector->panel.fixed_mode) {
                intel_fixed_panel_mode(intel_connector->panel.fixed_mode,
@@ -2211,8 +2211,8 @@ static void intel_dp_get_config(struct intel_encoder *encoder,
        int dotclock;
 
        tmp = I915_READ(intel_dp->output_reg);
-       if (tmp & DP_AUDIO_OUTPUT_ENABLE)
-               pipe_config->has_audio = true;
+
+       pipe_config->has_audio = tmp & DP_AUDIO_OUTPUT_ENABLE && port != PORT_A;
 
        if ((port == PORT_A) || !HAS_PCH_CPT(dev)) {
                if (tmp & DP_SYNC_HS_HIGH)