drm/i915/skl: Skylake moves AUX_CTL from PCH to CPU

So we can apply the old aux_ctl = dp_ctl + 0x10 rule again.

Reviewed-by: Thomas Wood <thomas.wood@intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 581ba1d..17c6910 100644 (file)
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -925,7 +925,16 @@ intel_dp_aux_init(struct intel_dp *intel_dp, struct intel_connector *connector)
                BUG();
        }
 
-       if (!HAS_DDI(dev))
+       /*
+        * The AUX_CTL register is usually DP_CTL + 0x10.
+        *
+        * On Haswell and Broadwell though:
+        *   - Both port A DDI_BUF_CTL and DDI_AUX_CTL are on the CPU
+        *   - Port B/C/D AUX channels are on the PCH, DDI_BUF_CTL on the CPU
+        *
+        * Skylake moves AUX_CTL back next to DDI_BUF_CTL, on the CPU.
+        */
+       if (!IS_HASWELL(dev) && !IS_BROADWELL(dev))
                intel_dp->aux_ch_ctl_reg = intel_dp->output_reg + 0x10;
 
        intel_dp->aux.name = name;