From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
It looks like frobbing the cmnreset line on pne PHY disturbs the other
PHY on chv. The result is a black screen. On HDMI it's just a flash of
black, but DP usually falls over and can't get back up.
As a workaround set up the power domains so that both common lane
wells power up and down together. I also tried leaving the cmnreset
deasserted even the if the power well goes down but that didn't seem
acceptable to the PHY.
Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/intel_pm.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 158c3f5..879d14c 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -6776,13 +6776,23 @@ static struct i915_power_well chv_power_wells[] = {
#endif
{
.name = "dpio-common-bc",
- .domains = CHV_DPIO_CMN_BC_POWER_DOMAINS,
+ /*
+ * XXX: cmnreset for one PHY seems to disturb the other.
+ * As a workaround keep both powered on at the same
+ * time for now.
+ */
+ .domains = CHV_DPIO_CMN_BC_POWER_DOMAINS | CHV_DPIO_CMN_D_POWER_DOMAINS,
.data = PUNIT_POWER_WELL_DPIO_CMN_BC,
.ops = &chv_dpio_cmn_power_well_ops,
},
{
.name = "dpio-common-d",
- .domains = CHV_DPIO_CMN_D_POWER_DOMAINS,
+ /*
+ * XXX: cmnreset for one PHY seems to disturb the other.
+ * As a workaround keep both powered on at the same
+ * time for now.
+ */
+ .domains = CHV_DPIO_CMN_BC_POWER_DOMAINS | CHV_DPIO_CMN_D_POWER_DOMAINS,
.data = PUNIT_POWER_WELL_DPIO_CMN_D,
.ops = &chv_dpio_cmn_power_well_ops,
},
--
1.8.5.5
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