6.11-stable review patch. If anyone has any objections, please let me know.
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From: Dillon Varone dillon.varone@amd.com
commit 9fc0cbcb6e45d6fc96ffd3bb7b6d6d28d693ff4d upstream.
If the nominal VBlank is too small, optimizing for stutter can cause the prefetch bandwidth to increase drasticaly, resulting in higher clock and power requirements. Only optimize if it is >3x the stutter latency.
Reviewed-by: Austin Zheng austin.zheng@amd.com Signed-off-by: Dillon Varone dillon.varone@amd.com Signed-off-by: Hamza Mahfooz hamza.mahfooz@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com (cherry picked from commit 003215f962cdf2265f126a3f4c9ad20917f87fca) Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/amd/display/dc/dml2/dml21/src/dml2_pmo/dml2_pmo_dcn4_fams2.c | 11 ++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)
--- a/drivers/gpu/drm/amd/display/dc/dml2/dml21/src/dml2_pmo/dml2_pmo_dcn4_fams2.c +++ b/drivers/gpu/drm/amd/display/dc/dml2/dml21/src/dml2_pmo/dml2_pmo_dcn4_fams2.c @@ -30,6 +30,7 @@ #include "dml2_pmo_dcn4_fams2.h"
static const double MIN_VACTIVE_MARGIN_PCT = 0.25; // We need more than non-zero margin because DET buffer granularity can alter vactive latency hiding +static const double MIN_BLANK_STUTTER_FACTOR = 3.0;
static const enum dml2_pmo_pstate_strategy base_strategy_list_1_display[][PMO_DCN4_MAX_DISPLAYS] = { // VActive Preferred @@ -2004,6 +2005,7 @@ bool pmo_dcn4_fams2_init_for_stutter(str struct dml2_pmo_instance *pmo = in_out->instance; bool stutter_period_meets_z8_eco = true; bool z8_stutter_optimization_too_expensive = false; + bool stutter_optimization_too_expensive = false; double line_time_us, vblank_nom_time_us;
unsigned int i; @@ -2025,10 +2027,15 @@ bool pmo_dcn4_fams2_init_for_stutter(str line_time_us = (double)in_out->base_display_config->display_config.stream_descriptors[i].timing.h_total / (in_out->base_display_config->display_config.stream_descriptors[i].timing.pixel_clock_khz * 1000) * 1000000; vblank_nom_time_us = line_time_us * in_out->base_display_config->display_config.stream_descriptors[i].timing.vblank_nom;
- if (vblank_nom_time_us < pmo->soc_bb->power_management_parameters.z8_stutter_exit_latency_us) { + if (vblank_nom_time_us < pmo->soc_bb->power_management_parameters.z8_stutter_exit_latency_us * MIN_BLANK_STUTTER_FACTOR) { z8_stutter_optimization_too_expensive = true; break; } + + if (vblank_nom_time_us < pmo->soc_bb->power_management_parameters.stutter_enter_plus_exit_latency_us * MIN_BLANK_STUTTER_FACTOR) { + stutter_optimization_too_expensive = true; + break; + } }
pmo->scratch.pmo_dcn4.num_stutter_candidates = 0; @@ -2044,7 +2051,7 @@ bool pmo_dcn4_fams2_init_for_stutter(str pmo->scratch.pmo_dcn4.z8_vblank_optimizable = false; }
- if (pmo->soc_bb->power_management_parameters.stutter_enter_plus_exit_latency_us > 0) { + if (!stutter_optimization_too_expensive && pmo->soc_bb->power_management_parameters.stutter_enter_plus_exit_latency_us > 0) { pmo->scratch.pmo_dcn4.optimal_vblank_reserved_time_for_stutter_us[pmo->scratch.pmo_dcn4.num_stutter_candidates] = (unsigned int)pmo->soc_bb->power_management_parameters.stutter_enter_plus_exit_latency_us; pmo->scratch.pmo_dcn4.num_stutter_candidates++; }