[PATCH v2 3/6] drm/i915: Remove the 8bpc shackles from DP MST

Ville Syrjala
2019-03-26T14:26:06Z

From: Ville Syrjälä <ville.syrjala@linux.intel.com>

Allow DP MST to output any color depth. This means deep color as
well as falling back to 6bpc if we would otherwise require too
much bandwidth.

TODO: We should probably extend bw_contstrained scheme to force
all streams on the link to 6bpc if we can't fit the new stream(s)
otherwise.

v2: Use a proper for-loop (Jani)

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com> #v1
---
drivers/gpu/drm/i915/intel_dp.c | 8 +-
drivers/gpu/drm/i915/intel_dp_mst.c | 117 +++++++++++++++++-----------
drivers/gpu/drm/i915/intel_drv.h | 8 ++
3 files changed, 80 insertions(+), 53 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 3a60d6f9a287..2aee526ed632 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1723,12 +1723,6 @@ void intel_dp_compute_rate(struct intel_dp *intel_dp, int port_clock,
}
}

-struct link_config_limits {
- int min_clock, max_clock;
- int min_lane_count, max_lane_count;
- int min_bpp, max_bpp;
-};
-
static bool intel_dp_source_supports_fec(struct intel_dp *intel_dp,
const struct intel_crtc_state *pipe_config)
{
@@ -1791,7 +1785,7 @@ static int intel_dp_compute_bpp(struct intel_dp *intel_dp,
}

/* Adjust link config limits based on compliance test requests. */
-static void
+void
intel_dp_adjust_compliance_config(struct intel_dp *intel_dp,
struct intel_crtc_state *pipe_config,
struct link_config_limits *limits)
diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
index 334176e814a1..484846e94427 100644
--- a/drivers/gpu/drm/i915/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/intel_dp_mst.c
@@ -29,41 +29,78 @@
#include <drm/drm_edid.h>
#include <drm/drm_probe_helper.h>

+static int intel_dp_mst_compute_link_config(struct intel_encoder *encoder,
+ struct intel_crtc_state *crtc_state,
+ struct drm_connector_state *conn_state,
+ struct link_config_limits *limits)
+{
+ struct drm_atomic_state *state = crtc_state->base.state;
+ struct intel_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
+ struct intel_dp *intel_dp = &intel_mst->primary->dp;
+ struct intel_connector *connector =
+ to_intel_connector(conn_state->connector);
+ const struct drm_display_mode *adjusted_mode =
+ &crtc_state->base.adjusted_mode;
+ void *port = connector->port;
+ bool constant_n = drm_dp_has_quirk(&intel_dp->desc,
+ DP_DPCD_QUIRK_CONSTANT_N);
+ int bpp, slots = -EINVAL;
+
+ crtc_state->lane_count = limits->max_lane_count;
+ crtc_state->port_clock = limits->max_clock;
+
+ for (bpp = limits->max_bpp; bpp >= limits->min_bpp; bpp -= 2 * 3) {
+ crtc_state->pipe_bpp = bpp;
+
+ crtc_state->pbn = drm_dp_calc_pbn_mode(adjusted_mode->crtc_clock,
+ crtc_state->pipe_bpp);
+
+ slots = drm_dp_atomic_find_vcpi_slots(state, &intel_dp->mst_mgr,
+ port, crtc_state->pbn);
+ if (slots == -EDEADLK)
+ return slots;
+ if (slots >= 0)
+ break;
+ }
+
+ if (slots < 0) {
+ DRM_DEBUG_KMS("failed finding vcpi slots:%d\n", slots);
+ return slots;
+ }
+
+ intel_link_compute_m_n(crtc_state->pipe_bpp,
+ crtc_state->lane_count,
+ adjusted_mode->crtc_clock,
+ crtc_state->port_clock,
+ &crtc_state->dp_m_n,
+ constant_n);
+ crtc_state->dp_m_n.tu = slots;
+
+ return 0;
+}
+
static int intel_dp_mst_compute_config(struct intel_encoder *encoder,
struct intel_crtc_state *pipe_config,
struct drm_connector_state *conn_state)
{
struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
struct intel_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
- struct intel_digital_port *intel_dig_port = intel_mst->primary;
- struct intel_dp *intel_dp = &intel_dig_port->dp;
- struct drm_connector *connector = conn_state->connector;
+ struct intel_dp *intel_dp = &intel_mst->primary->dp;
+ struct intel_connector *connector =
+ to_intel_connector(conn_state->connector);
struct intel_digital_connector_state *intel_conn_state =
to_intel_digital_connector_state(conn_state);
- void *port = to_intel_connector(connector)->port;
- struct drm_atomic_state *state = pipe_config->base.state;
- struct drm_crtc *crtc = pipe_config->base.crtc;
- struct drm_crtc_state *old_crtc_state =
- drm_atomic_get_old_crtc_state(state, crtc);
- int bpp;
- int lane_count, slots =
- to_intel_crtc_state(old_crtc_state)->dp_m_n.tu;
- const struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
- int mst_pbn;
- bool constant_n = drm_dp_has_quirk(&intel_dp->desc,
- DP_DPCD_QUIRK_CONSTANT_N);
+ const struct drm_display_mode *adjusted_mode =
+ &pipe_config->base.adjusted_mode;
+ void *port = connector->port;
+ struct link_config_limits limits;
+ int ret;

if (adjusted_mode->flags & DRM_MODE_FLAG_DBLSCAN)
return -EINVAL;

pipe_config->output_format = INTEL_OUTPUT_FORMAT_RGB;
pipe_config->has_pch_encoder = false;
- bpp = 24;
- if (intel_dp->compliance.test_data.bpc) {
- bpp = intel_dp->compliance.test_data.bpc * 3;
- DRM_DEBUG_KMS("Setting pipe bpp to %d\n",
- bpp);
- }

if (intel_conn_state->force_audio == HDMI_AUDIO_AUTO)
pipe_config->has_audio =
@@ -76,36 +113,25 @@ static int intel_dp_mst_compute_config(struct intel_encoder *encoder,
* for MST we always configure max link bw - the spec doesn't
* seem to suggest we should do otherwise.
*/
- lane_count = intel_dp_max_lane_count(intel_dp);
+ limits.min_clock =
+ limits.max_clock = intel_dp_max_link_rate(intel_dp);

- pipe_config->lane_count = lane_count;
+ limits.min_lane_count =
+ limits.max_lane_count = intel_dp_max_lane_count(intel_dp);

- pipe_config->pipe_bpp = bpp;
+ limits.min_bpp = 6 * 3;
+ limits.max_bpp = pipe_config->pipe_bpp;

- pipe_config->port_clock = intel_dp_max_link_rate(intel_dp);
+ intel_dp_adjust_compliance_config(intel_dp, pipe_config, &limits);
+
+ ret = intel_dp_mst_compute_link_config(encoder, pipe_config,
+ conn_state, &limits);
+ if (ret)
+ return ret;

pipe_config->limited_color_range =
intel_dp_limited_color_range(pipe_config, conn_state);

- mst_pbn = drm_dp_calc_pbn_mode(adjusted_mode->crtc_clock, bpp);
- pipe_config->pbn = mst_pbn;
-
- slots = drm_dp_atomic_find_vcpi_slots(state, &intel_dp->mst_mgr, port,
- mst_pbn);
- if (slots < 0) {
- DRM_DEBUG_KMS("failed finding vcpi slots:%d\n",
- slots);
- return slots;
- }
-
- intel_link_compute_m_n(bpp, lane_count,
- adjusted_mode->crtc_clock,
- pipe_config->port_clock,
- &pipe_config->dp_m_n,
- constant_n);
-
- pipe_config->dp_m_n.tu = slots;
-
if (IS_GEN9_LP(dev_priv))
pipe_config->lane_lat_optim_mask =
bxt_ddi_phy_calc_lane_lat_optim_mask(pipe_config->lane_count);
@@ -389,7 +415,6 @@ intel_dp_mst_mode_valid(struct drm_connector *connector,
struct intel_connector *intel_connector = to_intel_connector(connector);
struct intel_dp *intel_dp = intel_connector->mst_port;
int max_dotclk = to_i915(connector->dev)->max_dotclk_freq;
- int bpp = 24; /* MST uses fixed bpp */
int max_rate, mode_rate, max_lanes, max_link_clock;

if (drm_connector_is_unregistered(connector))
@@ -402,7 +427,7 @@ intel_dp_mst_mode_valid(struct drm_connector *connector,
max_lanes = intel_dp_max_lane_count(intel_dp);

max_rate = intel_dp_max_data_rate(max_link_clock, max_lanes);
- mode_rate = intel_dp_link_required(mode->clock, bpp);
+ mode_rate = intel_dp_link_required(mode->clock, 18);

/* TODO - validate mode against available PBN for link */
if (mode->clock < 10000)
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index ae62f6a6be22..e79954c6271c 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1909,6 +1909,14 @@ void intel_csr_ucode_suspend(struct drm_i915_private *);
void intel_csr_ucode_resume(struct drm_i915_private *);

/* intel_dp.c */
+struct link_config_limits {
+ int min_clock, max_clock;
+ int min_lane_count, max_lane_count;
+ int min_bpp, max_bpp;
+};
+void intel_dp_adjust_compliance_config(struct intel_dp *intel_dp,
+ struct intel_crtc_state *pipe_config,
+ struct link_config_limits *limits);
bool intel_dp_limited_color_range(const struct intel_crtc_state *crtc_state,
const struct drm_connector_state *conn_state);
bool intel_dp_port_enabled(struct drm_i915_private *dev_priv,
--
2.19.2