[Intel-gfx] [PATCH] drm/i915/dp: Correctly advertise HBR3 for GEN11+

[matthew.s.atwood at intel.com]

From: Matt Atwood <matthew.s.atwood at intel.com>

intel_dp_set_source_rates() calls intel_dp_is_edp(), which is unsafe to
use before encoder_type is set. This caused GEN11+ to incorrectly strip
HBR3 from source rates. Move intel_dp_set_source_rates() to after
encoder_type is set. Add comment to intel_dp_is_edp() describing unsafe
usages.

Fixes: b265a2a6255f5 ("drm/i915/icl: combo port vswing programming
changes per BSPEC")
Signed-off-by: Matt Atwood <matthew.s.atwood at intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 24b56b2a76c8..a4490bcad684 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -141,6 +141,8 @@ static const u8 valid_dsc_slicecount[] = {1, 2, 4};
  *
  * If a CPU or PCH DP output is attached to an eDP panel, this function
  * will return true, and false otherwise.
+ *
+ * This function is not safe to use prior to encoder type being set.
  */
 bool intel_dp_is_edp(struct intel_dp *intel_dp)
 {
@@ -7342,8 +7344,6 @@ intel_dp_init_connector(struct intel_digital_port *intel_dig_port,
 		 intel_dig_port->max_lanes, port_name(port)))
 		return false;
 
-	intel_dp_set_source_rates(intel_dp);
-
 	intel_dp->reset_link_params = true;
 	intel_dp->pps_pipe = INVALID_PIPE;
 	intel_dp->active_pipe = INVALID_PIPE;
@@ -7388,6 +7388,8 @@ intel_dp_init_connector(struct intel_digital_port *intel_dig_port,
 			type == DRM_MODE_CONNECTOR_eDP ? "eDP" : "DP",
 			port_name(port));
 
+	intel_dp_set_source_rates(intel_dp);
+
 	drm_connector_init(dev, connector, &intel_dp_connector_funcs, type);
 	drm_connector_helper_add(connector, &intel_dp_connector_helper_funcs);
 
-- 
2.17.2