diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index 1f6fbab7d4ada4c27a4238937f31a5175fec12db..9d6b76d1a52a7b5f3d749e9770dddc9d2900a83d 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -67,6 +67,63 @@ static int intel_dp_mst_check_constraints(struct drm_i915_private *i915, int bpp
return 0;
}
+static int intel_dp_mst_bw_overhead(const struct intel_crtc_state *crtc_state,
+ const struct intel_connector *connector,
+ bool ssc, bool dsc, int bpp)
+{
+ const struct drm_display_mode *adjusted_mode =
+ &crtc_state->hw.adjusted_mode;
+ unsigned long flags = DRM_DP_BW_OVERHEAD_MST;
+ int dsc_slice_count = 0;
+ int overhead;
+
+ flags |= intel_dp_is_uhbr(crtc_state) ? DRM_DP_BW_OVERHEAD_UHBR : 0;
+ flags |= ssc ? DRM_DP_BW_OVERHEAD_SSC_REF_CLK : 0;
+ flags |= crtc_state->fec_enable ? DRM_DP_BW_OVERHEAD_FEC : 0;
+
+ if (dsc) {
+ flags |= DRM_DP_BW_OVERHEAD_DSC;
+ /* TODO: add support for bigjoiner */
+ dsc_slice_count = intel_dp_dsc_get_slice_count(connector,
+ adjusted_mode->clock,
+ adjusted_mode->hdisplay,
+ false);
+ }
+
+ overhead = drm_dp_bw_overhead(crtc_state->lane_count,
+ adjusted_mode->hdisplay,
+ dsc_slice_count,
+ to_bpp_x16(bpp),
+ flags);
+
+ /*
+ * TODO: clarify whether a minimum required by the fixed FEC overhead
+ * in the bspec audio programming sequence is required here.
+ */
+ return max(overhead, intel_dp_bw_fec_overhead(crtc_state->fec_enable));
+}
+
+static void intel_dp_mst_compute_m_n(const struct intel_crtc_state *crtc_state,
+ const struct intel_connector *connector,
+ bool ssc, bool dsc,
+ int bpp,
+ struct intel_link_m_n *m_n)
+{
+ const struct drm_display_mode *adjusted_mode =
+ &crtc_state->hw.adjusted_mode;
+ int overhead = intel_dp_mst_bw_overhead(crtc_state,
+ connector,
+ ssc, dsc, bpp);
+
+ intel_link_compute_m_n(bpp, crtc_state->lane_count,
+ adjusted_mode->crtc_clock,
+ crtc_state->port_clock,
+ overhead,
+ m_n);
+
+ m_n->tu = DIV_ROUND_UP_ULL(mul_u32_u32(m_n->data_m, 64), m_n->data_n);
+}
+
static int intel_dp_mst_find_vcpi_slots_for_bpp(struct intel_encoder *encoder,
struct intel_crtc_state *crtc_state,
int max_bpp,
@@ -107,14 +164,40 @@ static int intel_dp_mst_find_vcpi_slots_for_bpp(struct intel_encoder *encoder,
crtc_state->lane_count);
for (bpp = max_bpp; bpp >= min_bpp; bpp -= step) {
+ struct intel_link_m_n remote_m_n;
+ int link_bpp;
+
drm_dbg_kms(&i915->drm, "Trying bpp %d\n", bpp);
ret = intel_dp_mst_check_constraints(i915, bpp, adjusted_mode, crtc_state, dsc);
if (ret)
continue;
- crtc_state->pbn = drm_dp_calc_pbn_mode(adjusted_mode->crtc_clock,
- bpp << 4);
+ link_bpp = dsc ? bpp :
+ intel_dp_output_bpp(crtc_state->output_format, bpp);
+
+ intel_dp_mst_compute_m_n(crtc_state, connector, false, dsc, link_bpp,
+ &crtc_state->dp_m_n);
+ intel_dp_mst_compute_m_n(crtc_state, connector, true, dsc, link_bpp,
+ &remote_m_n);
+
+ /*
+ * The TU size programmed to the HW determines which slots in
+ * an MTP frame are used for this stream, which needs to match
+ * the payload size programmed to the first downstream branch
+ * device's payload table.
+ *
+ * Note that atm the payload's PBN value DRM core sends via
+ * the ALLOCATE_PAYLOAD side-band message matches the payload
+ * size (which it calculates from the PBN value) it programs
+ * to the first branch device's payload table. The allocation
+ * in the payload table could be reduced though (to
+ * crtc_state->dp_m_n.tu), provided that the driver doesn't
+ * enable SSC on the corresponding link.
+ */
+ drm_WARN_ON(&i915->drm, remote_m_n.tu < crtc_state->dp_m_n.tu);
+ crtc_state->dp_m_n.tu = remote_m_n.tu;
+ crtc_state->pbn = remote_m_n.tu * mst_state->pbn_div;
slots = drm_dp_atomic_find_time_slots(state, &intel_dp->mst_mgr,
connector->port,
@@ -123,6 +206,8 @@ static int intel_dp_mst_find_vcpi_slots_for_bpp(struct intel_encoder *encoder,
return slots;
if (slots >= 0) {
+ drm_WARN_ON(&i915->drm, slots != remote_m_n.tu);
+
ret = drm_dp_mst_atomic_check(state);
/*
* If we got slots >= 0 and we can fit those based on check
@@ -156,10 +241,7 @@ static int intel_dp_mst_compute_link_config(struct intel_encoder *encoder,
struct drm_connector_state *conn_state,
struct link_config_limits *limits)
{
- const struct drm_display_mode *adjusted_mode =
- &crtc_state->hw.adjusted_mode;
int slots = -EINVAL;
- int link_bpp;
/*
* FIXME: allocate the BW according to link_bpp, which in the case of
@@ -174,16 +256,6 @@ static int intel_dp_mst_compute_link_config(struct intel_encoder *encoder,
if (slots < 0)
return slots;
- link_bpp = intel_dp_output_bpp(crtc_state->output_format, crtc_state->pipe_bpp);
-
- intel_link_compute_m_n(link_bpp,
- crtc_state->lane_count,
- adjusted_mode->crtc_clock,
- crtc_state->port_clock,
- intel_dp_bw_fec_overhead(crtc_state->fec_enable),
- &crtc_state->dp_m_n);
- crtc_state->dp_m_n.tu = slots;
-
return 0;
}
@@ -195,8 +267,6 @@ static int intel_dp_dsc_mst_compute_link_config(struct intel_encoder *encoder,
struct intel_connector *connector =
to_intel_connector(conn_state->connector);
struct drm_i915_private *i915 = to_i915(connector->base.dev);
- const struct drm_display_mode *adjusted_mode =
- &crtc_state->hw.adjusted_mode;
int slots = -EINVAL;
int i, num_bpc;
u8 dsc_bpc[3] = {};
@@ -271,14 +341,6 @@ static int intel_dp_dsc_mst_compute_link_config(struct intel_encoder *encoder,
return slots;
}
- intel_link_compute_m_n(crtc_state->dsc.compressed_bpp,
- crtc_state->lane_count,
- adjusted_mode->crtc_clock,
- crtc_state->port_clock,
- intel_dp_bw_fec_overhead(crtc_state->fec_enable),
- &crtc_state->dp_m_n);
- crtc_state->dp_m_n.tu = slots;
-
return 0;
}
static int intel_dp_mst_update_slots(struct intel_encoder *encoder,
@@ -987,6 +1049,18 @@ intel_dp_mst_mode_valid_ctx(struct drm_connector *connector,
if (ret)
return ret;
+ /*
+ * TODO:
+ * - Also check if compression would allow for the mode
+ * - Calculate the overhead using drm_dp_bw_overhead() /
+ * drm_dp_bw_channel_coding_efficiency(), similarly to the
+ * compute config code, as drm_dp_calc_pbn_mode() doesn't
+ * account with all the overheads.
+ * - Check here and during compute config the BW reported by
+ * DFP_Link_Available_Payload_Bandwidth_Number (or the
+ * corresponding link capabilities of the sink) in case the
+ * stream is uncompressed for it by the last branch device.
+ */
if (mode_rate > max_rate || mode->clock > max_dotclk ||
drm_dp_calc_pbn_mode(mode->clock, min_bpp << 4) > port->full_pbn) {
*status = MODE_CLOCK_HIGH;