Commit 35d2e4b7 authored by Jani Nikula's avatar Jani Nikula
Browse files

drm/i915/ddi: start distinguishing 128b/132b SST and MST at state readout 



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.deak@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: default avatarImre Deak <imre.deak@intel.com>
Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/119a773a0d4d74ad204435e462f8d12cb0ea4128.1735912293.git.jani.nikula@intel.com
parent 591b9170

drivers/gpu/drm/i915/display/intel_ddi.c

+23 −6
Original line number Diff line number Diff line
@@ -787,7 +787,7 @@ 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;
@@ -824,7 +824,6 @@ 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;
@@ -853,9 +852,10 @@ 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);

	}
@@ -865,6 +865,23 @@ 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",
@@ -875,9 +892,9 @@ 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;