Need some suggestions on what could be stored in slave_crtc_state to point to the master,
See my comments/questions inline
On Tue, Apr 23, 2019 at 08:48:58AM -0700, Manasi Navare wrote:
> In case of tiled displays when the two tiles are sent across two CRTCs
> over two separate DP SST connectors, we need a mechanism to synchronize
> the two CRTCs and their corresponding transcoders.
> So use the master-slave mode where there is one master corresponding
> to last horizontal and vertical tile that needs to be genlocked with
> all other slave tiles.
> This patch identifies saves the master CRTC pointer in all the slave
> CRTC states. This pointer is needed to select the master CRTC/transcoder
> while configuring transcoder port sync for the corresponding slaves.
>
> v2:
> * Move this to intel_mode_set_pipe_config(Jani N, Ville)
> * Use slave_bitmask to save associated slaves in master crtc state (Ville)
>
> Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
> Cc: Matt Roper <matthew.d.roper@xxxxxxxxx>
> Signed-off-by: Manasi Navare <manasi.d.navare@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/intel_display.c | 89 ++++++++++++++++++++++++++++
> drivers/gpu/drm/i915/intel_drv.h | 6 ++
> 2 files changed, 95 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index b276345779e6..92dea2231499 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -11316,6 +11316,86 @@ static int icl_check_nv12_planes(struct intel_crtc_state *crtc_state)
> return 0;
> }
>
> +static int icl_add_genlock_crtcs(struct drm_crtc *crtc,
> + struct intel_crtc_state *crtc_state,
> + struct drm_atomic_state *state)
> +{
> + struct drm_i915_private *dev_priv = to_i915(crtc_state->base.crtc->dev);
> + struct drm_connector *master_connector, *connector;
> + struct drm_connector_state *connector_state;
> + struct drm_connector_list_iter conn_iter;
> + struct drm_crtc *master_crtc = NULL;
> + struct drm_crtc_state *master_crtc_state;
> + int i, tile_group_id;
> +
> + if (INTEL_GEN(dev_priv) < 11)
> + return 0;
> +
> + /*
> + * In case of tiled displays there could be one or more slaves but there is
> + * only one master. Lets make the CRTC used by the connector corresponding
> + * to the last horizonal and last vertical tile a master/genlock CRTC.
> + * All the other CRTCs corresponding to other tiles of the same Tile group
> + * are the slave CRTCs and hold a pointer to their genlock CRTC.
> + */
> + for_each_new_connector_in_state(state, connector, connector_state, i) {
> + if (connector_state->crtc != crtc)
> + continue;
> + if (!connector->has_tile)
> + continue;
> + if (connector->tile_h_loc == connector->num_h_tile - 1 &&
> + connector->tile_v_loc == connector->num_v_tile - 1)
> + continue;
> + crtc_state->master_crtc = NULL;
> + tile_group_id = connector->tile_group->id;
> + drm_connector_list_iter_begin(&dev_priv->drm, &conn_iter);
> + drm_for_each_connector_iter(master_connector, &conn_iter) {
> + struct drm_connector_state *master_conn_state = NULL;
> +
> + if (!master_connector->has_tile)
> + continue;
> + if (master_connector->tile_h_loc != master_connector->num_h_tile - 1 ||
> + master_connector->tile_v_loc != master_connector->num_v_tile - 1)
> + continue;
> + if (master_connector->tile_group->id != tile_group_id)
> + continue;
> +
> + master_conn_state = drm_atomic_get_connector_state(state,
> + master_connector);
> + if (IS_ERR(master_conn_state)) {
> + drm_connector_list_iter_end(&conn_iter);
> + return PTR_ERR(master_conn_state);
> + }
> + if (master_conn_state->crtc) {
> + master_crtc = master_conn_state->crtc;
> + break;
> + }
> + }
> + drm_connector_list_iter_end(&conn_iter);
> +
> + if (!master_crtc) {
> + DRM_DEBUG_KMS("Could not add Master CRTC for Slave CRTC %d\n",
> + connector_state->crtc->base.id);
> + return -EINVAL;
> + }
> +
> + master_crtc_state = drm_atomic_get_crtc_state(state,
> + master_crtc);
> + if (IS_ERR(master_crtc_state))
> + return PTR_ERR(master_crtc_state);
> +
> + crtc_state->master_crtc = to_intel_crtc(master_crtc);
This stores a pointer to master_crtc which is used to obtain the master_crtc_state in crtc_enable
and obtain cpu_transcoder from that to configure master_select in TRANS PORT SYNC register
However, during the HW state readout we will read this register back for the slave to obtain the
master transcoder and I dont really have a clear path to find the master crtc from master transcoder
in order to do pipe_config_compare() in verify_crtc_state() which is currently causing the Pipe mismatch errors
Any suggestions on how this can be fixed? This assignment happens very early on before modeset_pipe_config,
so I dont believe I can use master_crtc_state->cpu_transcoder to obtain master transcoder.
Manasi
> + to_intel_crtc_state(master_crtc_state)->trans_port_sync_slaves |=
> + BIT(to_intel_crtc(crtc)->pipe);
> + DRM_DEBUG_KMS("Master CRTC = %d added for Slave CRTC = %d\n, slave bitmast = %d",
> + master_crtc->base.id,
> + crtc_state->base.crtc->base.id,
> + to_intel_crtc_state(master_crtc_state)->trans_port_sync_slaves);
> + }
> +
> + return 0;
> +}
> +
> static int intel_crtc_atomic_check(struct drm_crtc *crtc,
> struct drm_crtc_state *crtc_state)
> {
> @@ -11795,6 +11875,9 @@ clear_intel_crtc_state(struct intel_crtc_state *crtc_state)
> if (IS_G4X(dev_priv) ||
> IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
> saved_state->wm = crtc_state->wm;
> + if (INTEL_GEN(dev_priv) >= 11)
> + saved_state->trans_port_sync_slaves =
> + crtc_state->trans_port_sync_slaves;
>
> /* Keep base drm_crtc_state intact, only clear our extended struct */
> BUILD_BUG_ON(offsetof(struct intel_crtc_state, base));
> @@ -11888,6 +11971,12 @@ intel_modeset_pipe_config(struct drm_crtc *crtc,
> drm_mode_set_crtcinfo(&pipe_config->base.adjusted_mode,
> CRTC_STEREO_DOUBLE);
>
> + ret = icl_add_genlock_crtcs(crtc, pipe_config, state);
> + if (ret) {
> + DRM_DEBUG_KMS("\n8K Debug: Cannot assign genlock crtcs");
> + return ret;
> + }
> +
> /* Pass our mode to the connectors and the CRTC to give them a chance to
> * adjust it according to limitations or connector properties, and also
> * a chance to reject the mode entirely.
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index a38b9cff5cd0..8ae9cb662e28 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1082,6 +1082,12 @@ struct intel_crtc_state {
>
> /* Forward Error correction State */
> bool fec_enable;
> +
> + /* Pointer to master crtc in case of tiled displays */
> + struct intel_crtc *master_crtc;
> +
> + /* Bitmask to indicate slaves attached */
> + u8 trans_port_sync_slaves;
> };
>
> struct intel_crtc {
> --
> 2.19.1
>
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