On Fri, Dec 13, 2024 at 12:39:50PM +0200, Jani Nikula wrote:
> Extract intel_dp_mtp_tu_compute_config() independent of MST for figuring
> out the TU. Move the link configuration and mst state access to the
> callers. This should be usable for 128b/132b SST as well.
>
> The name isn't great, and it's all a bit too interconnected instead of
> having more generic building blocks, but should do the job.
>
> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/intel_dp_mst.c | 64 ++++++++++++++-------
> drivers/gpu/drm/i915/display/intel_dp_mst.h | 7 +++
> 2 files changed, 50 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> index 5218b1f7679a..8ad42c757ddf 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> @@ -209,31 +209,23 @@ static int intel_dp_mst_dsc_get_slice_count(const struct intel_connector *connec
> num_joined_pipes);
> }
>
> -static int mst_stream_find_vcpi_slots_for_bpp(struct intel_dp *intel_dp,
> - struct intel_crtc_state *crtc_state,
> - int max_bpp, int min_bpp,
> - struct link_config_limits *limits,
> - struct drm_connector_state *conn_state,
> - int step, bool dsc)
> +int intel_dp_mtp_tu_compute_config(struct intel_dp *intel_dp,
> + struct intel_crtc_state *crtc_state,
> + int max_bpp, int min_bpp,
> + struct drm_connector_state *conn_state,
> + int step, bool dsc)
> {
> struct intel_display *display = to_intel_display(intel_dp);
> struct drm_atomic_state *state = crtc_state->uapi.state;
> - struct drm_dp_mst_topology_state *mst_state;
> struct intel_connector *connector =
> to_intel_connector(conn_state->connector);
> const struct drm_display_mode *adjusted_mode =
> &crtc_state->hw.adjusted_mode;
> + fixed20_12 pbn_div;
> int bpp, slots = -EINVAL;
> int dsc_slice_count = 0;
> int max_dpt_bpp;
>
> - mst_state = drm_atomic_get_mst_topology_state(state, &intel_dp->mst_mgr);
> - if (IS_ERR(mst_state))
> - return PTR_ERR(mst_state);
> -
> - crtc_state->lane_count = limits->max_lane_count;
> - crtc_state->port_clock = limits->max_rate;
> -
> if (dsc) {
> if (!intel_dp_supports_fec(intel_dp, connector, crtc_state))
> return -EINVAL;
> @@ -241,8 +233,8 @@ static int mst_stream_find_vcpi_slots_for_bpp(struct intel_dp *intel_dp,
> crtc_state->fec_enable = !intel_dp_is_uhbr(crtc_state);
> }
>
> - mst_state->pbn_div = drm_dp_get_vc_payload_bw(crtc_state->port_clock,
> - crtc_state->lane_count);
> + pbn_div = drm_dp_get_vc_payload_bw(crtc_state->port_clock,
> + crtc_state->lane_count);
>
> max_dpt_bpp = intel_dp_mst_max_dpt_bpp(crtc_state, dsc);
> if (max_bpp > max_dpt_bpp) {
> @@ -302,7 +294,7 @@ static int mst_stream_find_vcpi_slots_for_bpp(struct intel_dp *intel_dp,
In the SST case the TUs are calculated for the first - only - link, the
overhead for that tracked in local_bw_overhead (since we don't enable SSC). So
crtc_state->dp_m_n at this point contains already what's needed for SST,
except for the 4/lane_count alignment. The things calculated for remote
links - PBN, remote_tu - are not needed for SST, so the TUs for SST
could be aligned separately and all the MST specific bits below extracted
to an MST helper.
> pbn.full = dfixed_const(intel_dp_mst_calc_pbn(adjusted_mode->crtc_clock,
> link_bpp_x16,
> remote_bw_overhead));
> - remote_tu = DIV_ROUND_UP(pbn.full, mst_state->pbn_div.full);
> + remote_tu = DIV_ROUND_UP(pbn.full, pbn_div.full);
>
> /*
> * Aligning the TUs ensures that symbols consisting of multiple
> @@ -320,15 +312,20 @@ static int mst_stream_find_vcpi_slots_for_bpp(struct intel_dp *intel_dp,
> * allocated for the whole path and the TUs allocated for the
> * first branch device's link also applies here.
> */
> - pbn.full = remote_tu * mst_state->pbn_div.full;
> + pbn.full = remote_tu * pbn_div.full;
> crtc_state->pbn = dfixed_trunc(pbn);
AFAICS crtc_state->pbn is not used anywhere else besides this function,
so could be removed from crtc_state while at it.
>
> drm_WARN_ON(display->drm, remote_tu < crtc_state->dp_m_n.tu);
> crtc_state->dp_m_n.tu = remote_tu;
>
> - slots = drm_dp_atomic_find_time_slots(state, &intel_dp->mst_mgr,
> - connector->port,
> - crtc_state->pbn);
> + if (intel_dp->is_mst)
> + slots = drm_dp_atomic_find_time_slots(state, &intel_dp->mst_mgr,
> + connector->port,
> + crtc_state->pbn);
> + else
> + /* FIXME: cross-check against pbn_div? */
> + slots = crtc_state->dp_m_n.tu;
The loop should be bounded like slots <= 64 then for SST (done by DRM
core in the MST helper above).
> +
> if (slots == -EDEADLK)
> return slots;
>
> @@ -356,6 +353,31 @@ static int mst_stream_find_vcpi_slots_for_bpp(struct intel_dp *intel_dp,
> return 0;
> }
>
> +static int mst_stream_find_vcpi_slots_for_bpp(struct intel_dp *intel_dp,
> + struct intel_crtc_state *crtc_state,
> + int max_bpp, int min_bpp,
> + struct link_config_limits *limits,
> + struct drm_connector_state *conn_state,
> + int step, bool dsc)
> +{
> + struct drm_atomic_state *state = crtc_state->uapi.state;
> + struct drm_dp_mst_topology_state *mst_state;
> +
> + mst_state = drm_atomic_get_mst_topology_state(state, &intel_dp->mst_mgr);
> + if (IS_ERR(mst_state))
> + return PTR_ERR(mst_state);
> +
> + crtc_state->lane_count = limits->max_lane_count;
> + crtc_state->port_clock = limits->max_rate;
> +
> + mst_state->pbn_div = drm_dp_get_vc_payload_bw(crtc_state->port_clock,
> + crtc_state->lane_count);
> +
> + return intel_dp_mtp_tu_compute_config(intel_dp, crtc_state,
> + max_bpp, min_bpp,
> + conn_state, step, dsc);
> +}
> +
> static int mst_stream_compute_link_config(struct intel_dp *intel_dp,
> struct intel_crtc_state *crtc_state,
> struct drm_connector_state *conn_state,
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.h b/drivers/gpu/drm/i915/display/intel_dp_mst.h
> index 8343804ce3f8..c6bdc1d190a4 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.h
> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.h
> @@ -8,6 +8,7 @@
>
> #include <linux/types.h>
>
> +struct drm_connector_state;
> struct intel_atomic_state;
> struct intel_crtc;
> struct intel_crtc_state;
> @@ -30,4 +31,10 @@ bool intel_dp_mst_crtc_needs_modeset(struct intel_atomic_state *state,
> void intel_dp_mst_prepare_probe(struct intel_dp *intel_dp);
> bool intel_dp_mst_verify_dpcd_state(struct intel_dp *intel_dp);
>
> +int intel_dp_mtp_tu_compute_config(struct intel_dp *intel_dp,
> + struct intel_crtc_state *crtc_state,
> + int max_bpp, int min_bpp,
> + struct drm_connector_state *conn_state,
> + int step, bool dsc);
> +
> #endif /* __INTEL_DP_MST_H__ */
> --
> 2.39.5
>
