[PATCH 2/2] drm/i915/display: Force full modeset for eDP

[Mika Kahola <mika.kahola@intel.com>]

Force full modeset for eDP when booting up. GOP programs
PLL parameters and hence, we would be able to use fastset
for eDP. However, with fastset we are not setting PLL values
from the driver and rely that GOP and driver PLL values match.
We have discovered that with some of the panels this is not
true and hence we would need to program PLL values by the
driver. The patch suggests a workaround as enabling full
modeset when booting up. This way we force the driver to
write the PLL values to the hw.

Signed-off-by: Mika Kahola <mika.kahola@intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index ab415f41924d..9699ded1eb5f 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -3319,6 +3319,7 @@ bool intel_dp_initial_fastset_check(struct intel_encoder *encoder,
 	 * of crtc_state->dsc, we have no way to ensure reliable fastset.
 	 * Remove once we have readout for DSC.
 	 */
+
 	if (crtc_state->dsc.compression_enable) {
 		drm_dbg_kms(&i915->drm, "[ENCODER:%d:%s] Forcing full modeset due to DSC being enabled\n",
 			    encoder->base.base.id, encoder->base.name);
@@ -3326,6 +3327,18 @@ bool intel_dp_initial_fastset_check(struct intel_encoder *encoder,
 		fastset = false;
 	}
 
+	/*
+	 * FIXME hack to force full modeset for eDP as not always BIOS written PLL
+	 * values does not match with the ones defined in the driver code
+	 */
+	if (!crtc_state->uapi.mode_changed &&
+	    intel_dp_is_edp(intel_dp)) {
+		drm_dbg_kms(&i915->drm, "Forcing full modeset for eDP\n");
+		crtc_state->uapi.mode_changed = true;
+		fastset = false;
+	}
+
+
 	return fastset;
 }
 
-- 
2.34.1