[PATCH 12/14] drm/i915: Turn on panel power before doing aux transfers

ville.syrjala
2014-08-18T19:21:16Z

From: Ville Syrjälä <ville.syrjala@linux.intel.com>

On VLV/CHV the panel power sequencer may need to be "kicked" a bit to
lock onto the new port, and that needs to happen before any aux
transfers are attempted if we want the aux transfers to actaully
succeed. So turn on panel power (part of the "kick") before aux
transfers (DPMS_ON + link training).

This also matches the documented modeset sequence better for pch
platforms. The documentation doesn't explicitly state anything about the
DPMS or link training DPCD writes, but the panel power on step is
always listed before link training is mentioned.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
drivers/gpu/drm/i915/intel_dp.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 4952783..28bc652 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -2275,10 +2275,10 @@ static void intel_enable_dp(struct intel_encoder *encoder)
return;

intel_edp_panel_vdd_on(intel_dp);
- intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_ON);
- intel_dp_start_link_train(intel_dp);
intel_edp_panel_on(intel_dp);
intel_edp_panel_vdd_off(intel_dp, true);
+ intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_ON);
+ intel_dp_start_link_train(intel_dp);
intel_dp_complete_link_train(intel_dp);
intel_dp_stop_link_train(intel_dp);
}
--
1.8.5.5