We'll want to distinguish 128b/132b SST and MST modes at state
readout. There's a catch, though. From the hardware perspective,
128b/132b SST and MST programming are pretty much the same. And we can't
really ask the sink at this point.
If we have more than one transcoder in 128b/132b mode associated with
the port, we can safely assume it's MST. But for MST with only a single
stream enabled, we are pretty much out of luck. Let's fall back to
looking at the software state, i.e. intel_dp->is_mst. It should be fine
for the state checker, but for hardware takeover at probe, we'll have to
trust the GOP has only enabled SST.
TODO: Not sure how this *or* our current code handles 128b/132b enabled
by GOP.
Cc: Imre Deak <imre.d...@intel.com>
Cc: Ville Syrjälä <ville.syrj...@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nik...@intel.com>
---
drivers/gpu/drm/i915/display/intel_ddi.c | 29 +++++++++++++++++++-----
1 file changed, 23 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c
b/drivers/gpu/drm/i915/display/intel_ddi.c
index 7b739b9c5a06..04118f2eea94 100644
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -786,7 +786,7 @@ static void intel_ddi_get_encoder_pipes(struct
intel_encoder *encoder,
intel_wakeref_t wakeref;
enum pipe p;
u32 tmp;
- u8 mst_pipe_mask;
+ u8 mst_pipe_mask = 0, dp128b132b_pipe_mask = 0;
*pipe_mask = 0;
*is_dp_mst = false;
@@ -823,7 +823,6 @@ static void intel_ddi_get_encoder_pipes(struct
intel_encoder *encoder,
goto out;
}
- mst_pipe_mask = 0;
for_each_pipe(dev_priv, p) {
enum transcoder cpu_transcoder = (enum transcoder)p;
u32 port_mask, ddi_select, ddi_mode;
@@ -852,9 +851,10 @@ static void intel_ddi_get_encoder_pipes(struct
intel_encoder *encoder,
ddi_mode = tmp & TRANS_DDI_MODE_SELECT_MASK;
- if (ddi_mode == TRANS_DDI_MODE_SELECT_DP_MST ||
- (ddi_mode == TRANS_DDI_MODE_SELECT_FDI_OR_128B132B &&
HAS_DP20(display)))
+ if (ddi_mode == TRANS_DDI_MODE_SELECT_DP_MST)
mst_pipe_mask |= BIT(p);
+ else if (ddi_mode == TRANS_DDI_MODE_SELECT_FDI_OR_128B132B &&
HAS_DP20(display))
+ dp128b132b_pipe_mask |= BIT(p);
*pipe_mask |= BIT(p);
}
@@ -864,6 +864,23 @@ static void intel_ddi_get_encoder_pipes(struct
intel_encoder *encoder,
"No pipe for [ENCODER:%d:%s] found\n",
encoder->base.base.id, encoder->base.name);
+ if (!mst_pipe_mask && dp128b132b_pipe_mask) {
+ struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
+
+ /*
+ * If we don't have 8b/10b MST, but have more than one
+ * transcoder in 128b/132b mode, we know it must be 128b/132b
+ * MST.
+ *
+ * Otherwise, we fall back to checking the current MST
+ * state. It's not accurate for hardware takeover at probe, but
+ * we don't expect MST to have been enabled at that point, and
+ * can assume it's SST.
+ */
+ if (hweight8(dp128b132b_pipe_mask) > 1 || intel_dp->is_mst)
+ mst_pipe_mask = dp128b132b_pipe_mask;
+ }
+
if (!mst_pipe_mask && hweight8(*pipe_mask) > 1) {
drm_dbg_kms(&dev_priv->drm,
"Multiple pipes for [ENCODER:%d:%s] (pipe_mask
%02x)\n",
@@ -874,9 +891,9 @@ static void intel_ddi_get_encoder_pipes(struct
intel_encoder *encoder,
if (mst_pipe_mask && mst_pipe_mask != *pipe_mask)
drm_dbg_kms(&dev_priv->drm,
- "Conflicting MST and non-MST state for
[ENCODER:%d:%s] (pipe_mask %02x mst_pipe_mask %02x)\n",
+ "Conflicting MST and non-MST state for
[ENCODER:%d:%s] (pipe masks: all %02x, MST %02x, 128b/132b %02x)\n",
encoder->base.base.id, encoder->base.name,
- *pipe_mask, mst_pipe_mask);
+ *pipe_mask, mst_pipe_mask, dp128b132b_pipe_mask);
else
*is_dp_mst = mst_pipe_mask;
--
2.39.5
