Workaround to avoid intermittent aux channel failures, per spec change.
v2: Don't mess with cpu dp aux divider (Paulo Zanoni)
Signed-off-by: Jani Nikula <jani.nikula at intel.com>
---
Untested.
---
drivers/gpu/drm/i915/intel_dp.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 482b5e5..f8474d1 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -353,10 +353,14 @@ intel_dp_aux_ch(struct intel_dp *intel_dp,
aux_clock_divider = 200; /* SNB & IVB eDP input clock at 400Mhz */
else
aux_clock_divider = 225; /* eDP input clock at 450Mhz */
- } else if (HAS_PCH_SPLIT(dev))
+ } else if (dev_priv->pch_id == INTEL_PCH_LPT_DEVICE_ID_TYPE) {
+ /* Workaround for non-ULT HSW */
+ aux_clock_divider = 74;
+ } else if (HAS_PCH_SPLIT(dev)) {
aux_clock_divider = DIV_ROUND_UP(intel_pch_rawclk(dev), 2);
- else
+ } else {
aux_clock_divider = intel_hrawclk(dev) / 2;
+ }
if (IS_GEN6(dev))
precharge = 3;
--
1.7.10.4
