On Wed, Jun 10, 2020 at 09:31:31PM +0300, Imre Deak wrote:
> On TGL+ the master transcoder's DP_TP_STATUS register should be used for
> the MST ACT status handling, so make sure we do that even in case of
> mulitple streams.
>
> This fixes an ACT timeout problem during disabling when using multiple
> streams. Not sure why this was not a problem during enabling (even the
> slave's DP_TP_STATUS signaled ACT correctly), but following the spec
> works in that case too, so let's do that.
>
> There is one more place using DP_TP_STATUS, FEC enabling, but I haven't
> found in BSpec which register to use in that case, so I leave the
> clarification of that for later.
>
> BSpec: 49190
>
> Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/intel_dp_mst.c | 47 +++++++++++++++++----
> 1 file changed, 39 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> index d18b406f2a7d..1c3654a117a9 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> @@ -316,6 +316,40 @@ intel_dp_mst_atomic_check(struct drm_connector *connector,
> return ret;
> }
>
> +static i915_reg_t
> +master_dp_tp_status_reg(const struct intel_crtc_state *crtc_state,
> + const struct intel_dp *intel_dp)
> +{
> + struct drm_i915_private *dev_priv = to_i915(crtc_state->uapi.crtc->dev);
> +
> + if (INTEL_GEN(dev_priv) >= 12)
> + return TGL_DP_TP_STATUS(crtc_state->mst_master_transcoder);
> +
> + return intel_dp->regs.dp_tp_status;
> +}
> +
> +static void clear_act_sent(const struct intel_crtc_state *crtc_state,
> + const struct intel_dp *intel_dp)
> +{
> + struct drm_i915_private *i915 = to_i915(crtc_state->uapi.crtc->dev);
> + i915_reg_t dp_tp_status_reg =
> + master_dp_tp_status_reg(crtc_state, intel_dp);
> +
> + intel_de_write(i915, dp_tp_status_reg,
> + intel_de_read(i915, dp_tp_status_reg));
Followup material:
Should we actually just clear the bit(s) we care about? No idea what
other stuff is in there.
> +}
> +
> +static bool wait_for_act_sent(const struct intel_crtc_state *crtc_state,
> + const struct intel_dp *intel_dp)
> +{
> + struct drm_i915_private *i915 = to_i915(crtc_state->uapi.crtc->dev);
> + i915_reg_t dp_tp_status_reg =
> + master_dp_tp_status_reg(crtc_state, intel_dp);
> +
> + return intel_de_wait_for_set(i915, dp_tp_status_reg,
> + DP_TP_STATUS_ACT_SENT, 1) == 0;
> +}
> +
> static void intel_mst_disable_dp(struct intel_atomic_state *state,
> struct intel_encoder *encoder,
> const struct intel_crtc_state *old_crtc_state,
> @@ -376,8 +410,7 @@ static void intel_mst_post_disable_dp(struct intel_atomic_state *state,
> TRANS_DDI_FUNC_CTL(old_crtc_state->cpu_transcoder),
> val);
>
> - if (intel_de_wait_for_set(dev_priv, intel_dp->regs.dp_tp_status,
> - DP_TP_STATUS_ACT_SENT, 1))
> + if (!wait_for_act_sent(old_crtc_state, intel_dp))
> drm_err(&dev_priv->drm,
> "Timed out waiting for ACT sent when disabling\n");
> drm_dp_check_act_status(&intel_dp->mst_mgr);
> @@ -443,7 +476,6 @@ static void intel_mst_pre_enable_dp(struct intel_atomic_state *state,
> struct intel_connector *connector =
> to_intel_connector(conn_state->connector);
> int ret;
> - u32 temp;
> bool first_mst_stream;
>
> /* MST encoders are bound to a crtc, not to a connector,
> @@ -476,8 +508,8 @@ static void intel_mst_pre_enable_dp(struct intel_atomic_state *state,
> drm_err(&dev_priv->drm, "failed to allocate vcpi\n");
>
> intel_dp->active_mst_links++;
> - temp = intel_de_read(dev_priv, intel_dp->regs.dp_tp_status);
> - intel_de_write(dev_priv, intel_dp->regs.dp_tp_status, temp);
> +
> + clear_act_sent(pipe_config, intel_dp);
>
> ret = drm_dp_update_payload_part1(&intel_dp->mst_mgr);
>
> @@ -513,9 +545,8 @@ static void intel_mst_enable_dp(struct intel_atomic_state *state,
> drm_dbg_kms(&dev_priv->drm, "active links %d\n",
> intel_dp->active_mst_links);
>
> - if (intel_de_wait_for_set(dev_priv, intel_dp->regs.dp_tp_status,
> - DP_TP_STATUS_ACT_SENT, 1))
> - drm_err(&dev_priv->drm, "Timed out waiting for ACT sent\n");
> + if (!wait_for_act_sent(pipe_config, intel_dp))
> + drm_err(&dev_priv->drm, "Timed out waiting for ACT sent when enabling\n");
>
> drm_dp_check_act_status(&intel_dp->mst_mgr);
>
> --
> 2.23.1
>
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--
Ville Syrjälä
Intel
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