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

[ Upstream commit 9fcb1704d1d51b12e2f03c78bca013d0cbbb7c98 ]

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>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 740d9ebbebdee8be38b60373e32e601e4fd5b1c3..a29db0a1da422e1011b637e6cc375426bc05f504 100644 (file)
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1037,7 +1037,7 @@ 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,
@@ -1879,8 +1879,8 @@ 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)