From: Fangzhi Zuo Jerry.Zuo@amd.com
commit 68dc1846c3a44d5e633be145c169ce2fd5420695 upstream.
8b/10b encoding needs to add 3% fec overhead into the pbn. In the Synapcis Cascaded MST hub, the first stage MST branch device needs the information to determine the timeslot count for the second stage MST branch device. Missing this overhead will leads to insufficient timeslot allocation.
Cc: stable@vger.kernel.org Cc: Mario Limonciello mario.limonciello@amd.com Reviewed-by: Hersen Wu hersenxs.wu@amd.com Acked-by: Qingqing Zhuo qingqing.zhuo@amd.com Signed-off-by: Fangzhi Zuo Jerry.Zuo@amd.com Tested-by: Daniel Wheeler daniel.wheeler@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c | 32 +++++++++--- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h | 3 + 2 files changed, 27 insertions(+), 8 deletions(-)
--- 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 @@ -646,12 +646,25 @@ struct dsc_mst_fairness_params { struct amdgpu_dm_connector *aconnector; };
-static int kbps_to_peak_pbn(int kbps) +static uint16_t get_fec_overhead_multiplier(struct dc_link *dc_link) +{ + u8 link_coding_cap; + uint16_t fec_overhead_multiplier_x1000 = PBN_FEC_OVERHEAD_MULTIPLIER_8B_10B; + + link_coding_cap = dc_link_dp_mst_decide_link_encoding_format(dc_link); + if (link_coding_cap == DP_128b_132b_ENCODING) + fec_overhead_multiplier_x1000 = PBN_FEC_OVERHEAD_MULTIPLIER_128B_132B; + + return fec_overhead_multiplier_x1000; +} + +static int kbps_to_peak_pbn(int kbps, uint16_t fec_overhead_multiplier_x1000) { u64 peak_kbps = kbps;
peak_kbps *= 1006; - peak_kbps = div_u64(peak_kbps, 1000); + peak_kbps *= fec_overhead_multiplier_x1000; + peak_kbps = div_u64(peak_kbps, 1000 * 1000); return (int) DIV64_U64_ROUND_UP(peak_kbps * 64, (54 * 8 * 1000)); }
@@ -745,11 +758,12 @@ static int increase_dsc_bpp(struct drm_a int link_timeslots_used; int fair_pbn_alloc; int ret = 0; + uint16_t fec_overhead_multiplier_x1000 = get_fec_overhead_multiplier(dc_link);
for (i = 0; i < count; i++) { if (vars[i + k].dsc_enabled) { initial_slack[i] = - kbps_to_peak_pbn(params[i].bw_range.max_kbps) - vars[i + k].pbn; + kbps_to_peak_pbn(params[i].bw_range.max_kbps, fec_overhead_multiplier_x1000) - vars[i + k].pbn; bpp_increased[i] = false; remaining_to_increase += 1; } else { @@ -845,6 +859,7 @@ static int try_disable_dsc(struct drm_at int next_index; int remaining_to_try = 0; int ret; + uint16_t fec_overhead_multiplier_x1000 = get_fec_overhead_multiplier(dc_link);
for (i = 0; i < count; i++) { if (vars[i + k].dsc_enabled @@ -874,7 +889,7 @@ static int try_disable_dsc(struct drm_at if (next_index == -1) break;
- vars[next_index].pbn = kbps_to_peak_pbn(params[next_index].bw_range.stream_kbps); + vars[next_index].pbn = kbps_to_peak_pbn(params[next_index].bw_range.stream_kbps, fec_overhead_multiplier_x1000); ret = drm_dp_atomic_find_time_slots(state, params[next_index].port->mgr, params[next_index].port, @@ -887,7 +902,7 @@ static int try_disable_dsc(struct drm_at 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); + vars[next_index].pbn = kbps_to_peak_pbn(params[next_index].bw_range.max_kbps, fec_overhead_multiplier_x1000); ret = drm_dp_atomic_find_time_slots(state, params[next_index].port->mgr, params[next_index].port, @@ -916,6 +931,7 @@ static int compute_mst_dsc_configs_for_l int count = 0; int i, k, ret; bool debugfs_overwrite = false; + uint16_t fec_overhead_multiplier_x1000 = get_fec_overhead_multiplier(dc_link);
memset(params, 0, sizeof(params));
@@ -977,7 +993,7 @@ static int compute_mst_dsc_configs_for_l /* Try no compression */ for (i = 0; i < count; i++) { vars[i + k].aconnector = params[i].aconnector; - vars[i + k].pbn = kbps_to_peak_pbn(params[i].bw_range.stream_kbps); + vars[i + k].pbn = kbps_to_peak_pbn(params[i].bw_range.stream_kbps, fec_overhead_multiplier_x1000); vars[i + k].dsc_enabled = false; vars[i + k].bpp_x16 = 0; ret = drm_dp_atomic_find_time_slots(state, params[i].port->mgr, params[i].port, @@ -996,7 +1012,7 @@ static int compute_mst_dsc_configs_for_l /* Try max compression */ for (i = 0; i < count; i++) { if (params[i].compression_possible && params[i].clock_force_enable != DSC_CLK_FORCE_DISABLE) { - vars[i + k].pbn = kbps_to_peak_pbn(params[i].bw_range.min_kbps); + vars[i + k].pbn = kbps_to_peak_pbn(params[i].bw_range.min_kbps, fec_overhead_multiplier_x1000); vars[i + k].dsc_enabled = true; vars[i + k].bpp_x16 = params[i].bw_range.min_target_bpp_x16; ret = drm_dp_atomic_find_time_slots(state, params[i].port->mgr, @@ -1004,7 +1020,7 @@ static int compute_mst_dsc_configs_for_l if (ret < 0) return ret; } else { - vars[i + k].pbn = kbps_to_peak_pbn(params[i].bw_range.stream_kbps); + vars[i + k].pbn = kbps_to_peak_pbn(params[i].bw_range.stream_kbps, fec_overhead_multiplier_x1000); vars[i + k].dsc_enabled = false; vars[i + k].bpp_x16 = 0; ret = drm_dp_atomic_find_time_slots(state, params[i].port->mgr, --- 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 @@ -46,6 +46,9 @@ #define SYNAPTICS_CASCADED_HUB_ID 0x5A #define IS_SYNAPTICS_CASCADED_PANAMERA(devName, data) ((IS_SYNAPTICS_PANAMERA(devName) && ((int)data[2] == SYNAPTICS_CASCADED_HUB_ID)) ? 1 : 0)
+#define PBN_FEC_OVERHEAD_MULTIPLIER_8B_10B 1031 +#define PBN_FEC_OVERHEAD_MULTIPLIER_128B_132B 1000 + struct amdgpu_display_manager; struct amdgpu_dm_connector;