[PATCH v9 15/18] drm/amd/display: MST DSC compute fair share
Lyude Paul
lyude at redhat.com
Fri Dec 20 21:44:59 UTC 2019
Acked-by: Lyude Paul <lyude at redhat.com>
On Fri, 2019-12-13 at 15:08 -0500, mikita.lipski at amd.com wrote:
> From: David Francis <David.Francis at amd.com>
>
> If there is limited link bandwidth on a MST network,
> it must be divided fairly between the streams on that network
>
> Implement an algorithm to determine the correct DSC config
> for each stream
>
> The algorithm:
> This
> [ ] ( )
> represents the range of bandwidths possible for a given stream.
> The [] area represents the range of DSC configs, and the ()
> represents no DSC. The bandwidth used increases from left to right.
>
> First, try disabling DSC on all streams
> [ ] (|)
> [ ] (|)
> Check this against the bandwidth limits of the link and each branch
> (including each endpoint). If it passes, the job is done
>
> Second, try maximum DSC compression on all streams
> that support DSC
> [| ] ( )
> [| ] ( )
> If this does not pass, then enabling this combination of streams
> is impossible
>
> Otherwise, divide the remaining bandwidth evenly amongst the streams
> [ | ] ( )
> [ | ] ( )
>
> If one or more of the streams reach minimum compression, evenly
> divide the reamining bandwidth amongst the remaining streams
> [ |] ( )
> [ |] ( )
> [ | ] ( )
> [ | ] ( )
>
> If all streams can reach minimum compression, disable compression
> greedily
> [ |] ( )
> [ |] ( )
> [ ] (|)
>
> Perform this algorithm on each full update, on each MST link
> with at least one DSC stream on it
>
> After the configs are computed, call
> dcn20_add_dsc_to_stream_resource on each stream with DSC enabled.
> It is only after all streams are created that we can know which
> of them will need DSC.
>
> Do all of this at the end of amdgpu atomic check. If it fails,
> fail check; This combination of timings cannot be supported.
>
> v2: Use drm_dp_mst_atomic_check to validate bw for certain dsc
> configurations
>
> v3: Use dc_dsc_policy structure to get min and max bpp rate
> for DSC configuration
>
> Cc: Lyude Paul <lyude at redhat.com>
> Cc: Manasi Navare <manasi.d.navare at intel.com>
> Reviewed-by: Wenjing Liu <Wenjing.Liu at amd.com>
> Signed-off-by: David Francis <David.Francis at amd.com>
> Signed-off-by: Mikita Lipski <mikita.lipski at amd.com>
> ---
> .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 3 +
> .../display/amdgpu_dm/amdgpu_dm_mst_types.c | 364 ++++++++++++++++++
> .../display/amdgpu_dm/amdgpu_dm_mst_types.h | 3 +
> .../drm/amd/display/dc/dcn20/dcn20_resource.c | 7 +-
> .../drm/amd/display/dc/dcn20/dcn20_resource.h | 1 +
> 5 files changed, 376 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> index 753a79734817..93a230d956ee 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -8095,6 +8095,9 @@ static int amdgpu_dm_atomic_check(struct drm_device
> *dev,
> if (ret)
> goto fail;
>
> + if (!compute_mst_dsc_configs_for_state(state, dm_state-
> >context))
> + goto fail;
> +
> if (dc_validate_global_state(dc, dm_state->context, false) !=
> DC_OK) {
> ret = -EINVAL;
> goto fail;
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> index c376c8ccd391..6d13d1c33530 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> @@ -40,6 +40,10 @@
> #if defined(CONFIG_DEBUG_FS)
> #include "amdgpu_dm_debugfs.h"
> #endif
> +
> +
> +#include "dc/dcn20/dcn20_resource.h"
> +
> /* #define TRACE_DPCD */
>
> #ifdef TRACE_DPCD
> @@ -499,3 +503,363 @@ int dm_mst_get_pbn_divider(struct dc_link *link)
> return dc_link_bandwidth_kbps(link,
> dc_link_get_link_cap(link)) / (8 * 1000 * 54);
> }
> +
> +struct dsc_mst_fairness_params {
> + struct dc_crtc_timing *timing;
> + struct dc_sink *sink;
> + struct dc_dsc_bw_range bw_range;
> + bool compression_possible;
> + struct drm_dp_mst_port *port;
> +};
> +
> +struct dsc_mst_fairness_vars {
> + int pbn;
> + bool dsc_enabled;
> + int bpp_x16;
> +};
> +
> +static int kbps_to_peak_pbn(int kbps)
> +{
> + u64 peak_kbps = kbps;
> +
> + peak_kbps *= 1006;
> + peak_kbps /= 1000;
> + return (int) DIV_ROUND_UP(peak_kbps * 64, (54 * 8 * 1000));
> +}
> +
> +static void set_dsc_configs_from_fairness_vars(struct
> dsc_mst_fairness_params *params,
> + struct dsc_mst_fairness_vars *vars,
> + int count)
> +{
> + int i;
> +
> + for (i = 0; i < count; i++) {
> + memset(¶ms[i].timing->dsc_cfg, 0, sizeof(params[i].timing-
> >dsc_cfg));
> + if (vars[i].dsc_enabled && dc_dsc_compute_config(
> + params[i].sink->ctx->dc->res_pool-
> >dscs[0],
> + ¶ms[i].sink-
> >sink_dsc_caps.dsc_dec_caps,
> + params[i].sink->ctx->dc-
> >debug.dsc_min_slice_height_override,
> + 0,
> + params[i].timing,
> + ¶ms[i].timing->dsc_cfg)) {
> + params[i].timing->flags.DSC = 1;
> + params[i].timing->dsc_cfg.bits_per_pixel =
> vars[i].bpp_x16;
> + } else {
> + params[i].timing->flags.DSC = 0;
> + }
> + }
> +}
> +
> +static int bpp_x16_from_pbn(struct dsc_mst_fairness_params param, int pbn)
> +{
> + struct dc_dsc_config dsc_config;
> + u64 kbps;
> +
> + kbps = (u64)pbn * 994 * 8 * 54 / 64;
> + dc_dsc_compute_config(
> + param.sink->ctx->dc->res_pool->dscs[0],
> + ¶m.sink->sink_dsc_caps.dsc_dec_caps,
> + param.sink->ctx->dc-
> >debug.dsc_min_slice_height_override,
> + (int) kbps, param.timing, &dsc_config);
> +
> + return dsc_config.bits_per_pixel;
> +}
> +
> +static void increase_dsc_bpp(struct drm_atomic_state *state,
> + struct dc_link *dc_link,
> + struct dsc_mst_fairness_params *params,
> + struct dsc_mst_fairness_vars *vars,
> + int count)
> +{
> + int i;
> + bool bpp_increased[MAX_PIPES];
> + int initial_slack[MAX_PIPES];
> + int min_initial_slack;
> + int next_index;
> + int remaining_to_increase = 0;
> + int pbn_per_timeslot;
> + int link_timeslots_used;
> + int fair_pbn_alloc;
> +
> + for (i = 0; i < count; i++) {
> + if (vars[i].dsc_enabled) {
> + initial_slack[i] =
> kbps_to_peak_pbn(params[i].bw_range.max_kbps) - vars[i].pbn;
> + bpp_increased[i] = false;
> + remaining_to_increase += 1;
> + } else {
> + initial_slack[i] = 0;
> + bpp_increased[i] = true;
> + }
> + }
> +
> + pbn_per_timeslot = dc_link_bandwidth_kbps(dc_link,
> + dc_link_get_link_cap(dc_link)) / (8 * 1000 * 54);
> +
> + while (remaining_to_increase) {
> + next_index = -1;
> + min_initial_slack = -1;
> + for (i = 0; i < count; i++) {
> + if (!bpp_increased[i]) {
> + if (min_initial_slack == -1 ||
> min_initial_slack > initial_slack[i]) {
> + min_initial_slack = initial_slack[i];
> + next_index = i;
> + }
> + }
> + }
> +
> + if (next_index == -1)
> + break;
> +
> + link_timeslots_used = 0;
> +
> + for (i = 0; i < count; i++)
> + link_timeslots_used += DIV_ROUND_UP(vars[i].pbn,
> pbn_per_timeslot);
> +
> + fair_pbn_alloc = (63 - link_timeslots_used) /
> remaining_to_increase * pbn_per_timeslot;
> +
> + if (initial_slack[next_index] > fair_pbn_alloc) {
> + vars[next_index].pbn += fair_pbn_alloc;
> + drm_dp_atomic_find_vcpi_slots(state,
> + params[next_index].port-
> >mgr,
> + params[next_index].port,
> + vars[next_index].pbn,
> + dm_mst_get_pbn_divider(d
> c_link));
> + if (!drm_dp_mst_atomic_check(state)) {
> + vars[next_index].bpp_x16 =
> bpp_x16_from_pbn(params[next_index], vars[next_index].pbn);
> + } else {
> + vars[next_index].pbn -= fair_pbn_alloc;
> + drm_dp_atomic_find_vcpi_slots(state,
> + params[next_index].port-
> >mgr,
> + params[next_index].port,
> + vars[next_index].pbn,
> + dm_mst_get_pbn_divider(d
> c_link));
> + }
> + } else {
> + vars[next_index].pbn += initial_slack[next_index];
> + drm_dp_atomic_find_vcpi_slots(state,
> + params[next_index].port-
> >mgr,
> + params[next_index].port,
> + vars[next_index].pbn,
> + dm_mst_get_pbn_divider(d
> c_link));
> + if (!drm_dp_mst_atomic_check(state)) {
> + vars[next_index].bpp_x16 =
> params[next_index].bw_range.max_target_bpp_x16;
> + } else {
> + vars[next_index].pbn -=
> initial_slack[next_index];
> + drm_dp_atomic_find_vcpi_slots(state,
> + params[next_index].port-
> >mgr,
> + params[next_index].port,
> + vars[next_index].pbn,
> + dm_mst_get_pbn_divider(d
> c_link));
> + }
> + }
> +
> + bpp_increased[next_index] = true;
> + remaining_to_increase--;
> + }
> +}
> +
> +static void try_disable_dsc(struct drm_atomic_state *state,
> + struct dc_link *dc_link,
> + struct dsc_mst_fairness_params *params,
> + struct dsc_mst_fairness_vars *vars,
> + int count)
> +{
> + int i;
> + bool tried[MAX_PIPES];
> + int kbps_increase[MAX_PIPES];
> + int max_kbps_increase;
> + int next_index;
> + int remaining_to_try = 0;
> +
> + for (i = 0; i < count; i++) {
> + if (vars[i].dsc_enabled && vars[i].bpp_x16 ==
> params[i].bw_range.max_target_bpp_x16) {
> + kbps_increase[i] = params[i].bw_range.stream_kbps -
> params[i].bw_range.max_kbps;
> + tried[i] = false;
> + remaining_to_try += 1;
> + } else {
> + kbps_increase[i] = 0;
> + tried[i] = true;
> + }
> + }
> +
> + while (remaining_to_try) {
> + next_index = -1;
> + max_kbps_increase = -1;
> + for (i = 0; i < count; i++) {
> + if (!tried[i]) {
> + if (max_kbps_increase == -1 ||
> max_kbps_increase < kbps_increase[i]) {
> + max_kbps_increase = kbps_increase[i];
> + next_index = i;
> + }
> + }
> + }
> +
> + if (next_index == -1)
> + break;
> +
> + vars[next_index].pbn =
> kbps_to_peak_pbn(params[next_index].bw_range.stream_kbps);
> + drm_dp_atomic_find_vcpi_slots(state,
> + params[next_index].port->mgr,
> + params[next_index].port,
> + vars[next_index].pbn,
> + 0);
> +
> + if (!drm_dp_mst_atomic_check(state)) {
> + vars[next_index].dsc_enabled = false;
> + vars[next_index].bpp_x16 = 0;
> + } else {
> + vars[next_index].pbn =
> kbps_to_peak_pbn(params[next_index].bw_range.max_kbps);
> + drm_dp_atomic_find_vcpi_slots(state,
> + params[next_index].port->mgr,
> + params[next_index].port,
> + vars[next_index].pbn,
> + dm_mst_get_pbn_divider(dc_link))
> ;
> + }
> +
> + tried[next_index] = true;
> + remaining_to_try--;
> + }
> +}
> +
> +static bool compute_mst_dsc_configs_for_link(struct drm_atomic_state
> *state,
> + struct dc_state *dc_state,
> + struct dc_link *dc_link)
> +{
> + int i;
> + struct dc_stream_state *stream;
> + struct dsc_mst_fairness_params params[MAX_PIPES];
> + struct dsc_mst_fairness_vars vars[MAX_PIPES];
> + struct amdgpu_dm_connector *aconnector;
> + int count = 0;
> +
> + memset(params, 0, sizeof(params));
> +
> + /* Set up params */
> + for (i = 0; i < dc_state->stream_count; i++) {
> + struct dc_dsc_policy dsc_policy = {0};
> +
> + stream = dc_state->streams[i];
> +
> + if (stream->link != dc_link)
> + continue;
> +
> + stream->timing.flags.DSC = 0;
> +
> + params[count].timing = &stream->timing;
> + params[count].sink = stream->sink;
> + aconnector = (struct amdgpu_dm_connector *)stream-
> >dm_stream_context;
> + params[count].port = aconnector->port;
> + params[count].compression_possible = stream->sink-
> >sink_dsc_caps.dsc_dec_caps.is_dsc_supported;
> + dc_dsc_get_policy_for_timing(params[count].timing,
> &dsc_policy);
> + if (!dc_dsc_compute_bandwidth_range(
> + stream->sink->ctx->dc->res_pool->dscs[0],
> + stream->sink->ctx->dc-
> >debug.dsc_min_slice_height_override,
> + dsc_policy.min_target_bpp,
> + dsc_policy.max_target_bpp,
> + &stream->sink->sink_dsc_caps.dsc_dec_caps,
> + &stream->timing, ¶ms[count].bw_range))
> + params[count].bw_range.stream_kbps =
> dc_bandwidth_in_kbps_from_timing(&stream->timing);
> +
> + count++;
> + }
> + /* Try no compression */
> + for (i = 0; i < count; i++) {
> + vars[i].pbn =
> kbps_to_peak_pbn(params[i].bw_range.stream_kbps);
> + vars[i].dsc_enabled = false;
> + vars[i].bpp_x16 = 0;
> + drm_dp_atomic_find_vcpi_slots(state,
> + params[i].port->mgr,
> + params[i].port,
> + vars[i].pbn,
> + 0);
> + }
> + if (!drm_dp_mst_atomic_check(state)) {
> + set_dsc_configs_from_fairness_vars(params, vars, count);
> + return true;
> + }
> +
> + /* Try max compression */
> + for (i = 0; i < count; i++) {
> + if (params[i].compression_possible) {
> + vars[i].pbn =
> kbps_to_peak_pbn(params[i].bw_range.min_kbps);
> + vars[i].dsc_enabled = true;
> + vars[i].bpp_x16 =
> params[i].bw_range.min_target_bpp_x16;
> + drm_dp_atomic_find_vcpi_slots(state,
> + params[i].port->mgr,
> + params[i].port,
> + vars[i].pbn,
> + dm_mst_get_pbn_divider(dc_link))
> ;
> + } else {
> + vars[i].pbn =
> kbps_to_peak_pbn(params[i].bw_range.stream_kbps);
> + vars[i].dsc_enabled = false;
> + vars[i].bpp_x16 = 0;
> + drm_dp_atomic_find_vcpi_slots(state,
> + params[i].port->mgr,
> + params[i].port,
> + vars[i].pbn,
> + 0);
> + }
> + }
> + if (drm_dp_mst_atomic_check(state))
> + return false;
> +
> + /* Optimize degree of compression */
> + increase_dsc_bpp(state, dc_link, params, vars, count);
> +
> + try_disable_dsc(state, dc_link, params, vars, count);
> +
> + set_dsc_configs_from_fairness_vars(params, vars, count);
> +
> + return true;
> +}
> +
> +bool compute_mst_dsc_configs_for_state(struct drm_atomic_state *state,
> + struct dc_state *dc_state)
> +{
> + int i, j;
> + struct dc_stream_state *stream;
> + bool computed_streams[MAX_PIPES];
> + struct amdgpu_dm_connector *aconnector;
> +
> + for (i = 0; i < dc_state->stream_count; i++)
> + computed_streams[i] = false;
> +
> + for (i = 0; i < dc_state->stream_count; i++) {
> + stream = dc_state->streams[i];
> +
> + if (stream->signal != SIGNAL_TYPE_DISPLAY_PORT_MST)
> + continue;
> +
> + aconnector = (struct amdgpu_dm_connector *)stream-
> >dm_stream_context;
> +
> + if (!aconnector || !aconnector->dc_sink)
> + continue;
> +
> + if (!aconnector->dc_sink-
> >sink_dsc_caps.dsc_dec_caps.is_dsc_supported)
> + continue;
> +
> + if (computed_streams[i])
> + continue;
> +
> + mutex_lock(&aconnector->mst_mgr.lock);
> + if (!compute_mst_dsc_configs_for_link(state, dc_state, stream-
> >link)) {
> + mutex_unlock(&aconnector->mst_mgr.lock);
> + return false;
> + }
> + mutex_unlock(&aconnector->mst_mgr.lock);
> +
> + for (j = 0; j < dc_state->stream_count; j++) {
> + if (dc_state->streams[j]->link == stream->link)
> + computed_streams[j] = true;
> + }
> + }
> +
> + for (i = 0; i < dc_state->stream_count; i++) {
> + stream = dc_state->streams[i];
> +
> + if (stream->timing.flags.DSC == 1)
> + dcn20_add_dsc_to_stream_resource(stream->ctx->dc,
> dc_state, stream);
> + }
> +
> + return true;
> +}
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h
> b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h
> index a553ea046185..d451ce9cecc0 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h
> @@ -34,4 +34,7 @@ int dm_mst_get_pbn_divider(struct dc_link *link);
> void amdgpu_dm_initialize_dp_connector(struct amdgpu_display_manager *dm,
> struct amdgpu_dm_connector
> *aconnector);
>
> +
> +bool compute_mst_dsc_configs_for_state(struct drm_atomic_state *state,
> + struct dc_state *dc_state);
> #endif
> diff --git a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c
> b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c
> index 47adcd4555ec..b1935f5d9cb8 100644
> --- a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c
> +++ b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c
> @@ -1564,7 +1564,7 @@ static void release_dsc(struct resource_context
> *res_ctx,
>
>
>
> -static enum dc_status add_dsc_to_stream_resource(struct dc *dc,
> +enum dc_status dcn20_add_dsc_to_stream_resource(struct dc *dc,
> struct dc_state *dc_ctx,
> struct dc_stream_state *dc_stream)
> {
> @@ -1579,6 +1579,9 @@ static enum dc_status
> add_dsc_to_stream_resource(struct dc *dc,
> if (pipe_ctx->stream != dc_stream)
> continue;
>
> + if (pipe_ctx->stream_res.dsc)
> + continue;
> +
> acquire_dsc(&dc_ctx->res_ctx, pool, &pipe_ctx->stream_res.dsc,
> i);
>
> /* The number of DSCs can be less than the number of pipes */
> @@ -1627,7 +1630,7 @@ enum dc_status dcn20_add_stream_to_ctx(struct dc *dc,
> struct dc_state *new_ctx,
>
> /* Get a DSC if required and available */
> if (result == DC_OK && dc_stream->timing.flags.DSC)
> - result = add_dsc_to_stream_resource(dc, new_ctx, dc_stream);
> + result = dcn20_add_dsc_to_stream_resource(dc, new_ctx,
> dc_stream);
>
> if (result == DC_OK)
> result = dcn20_build_mapped_resource(dc, new_ctx, dc_stream);
> diff --git a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.h
> b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.h
> index 840ca66c34e1..f5893840b79b 100644
> --- a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.h
> +++ b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.h
> @@ -157,6 +157,7 @@ void dcn20_calculate_dlg_params(
>
> enum dc_status dcn20_build_mapped_resource(const struct dc *dc, struct
> dc_state *context, struct dc_stream_state *stream);
> enum dc_status dcn20_add_stream_to_ctx(struct dc *dc, struct dc_state
> *new_ctx, struct dc_stream_state *dc_stream);
> +enum dc_status dcn20_add_dsc_to_stream_resource(struct dc *dc, struct
> dc_state *dc_ctx, struct dc_stream_state *dc_stream);
> enum dc_status dcn20_remove_stream_from_ctx(struct dc *dc, struct dc_state
> *new_ctx, struct dc_stream_state *dc_stream);
> enum dc_status dcn20_get_default_swizzle_mode(struct dc_plane_state
> *plane_state);
>
--
Cheers,
Lyude Paul
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