Commit 338567d1 authored by Fangzhi Zuo's avatar Fangzhi Zuo Committed by Alex Deucher
Browse files

drm/amd/display: Fix MST BW calculation Regression 



[Why & How]
Revert commit 8b2cb32c
("drm/amd/display: FEC overhead should be checked once for mst slot nums")
Because causes bw calculation regression

Cc: mario.limonciello@amd.com
Cc: alexander.deucher@amd.com
Reported-by: default avatar <jirislaby@kernel.org>
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3495
Closes: https://bugzilla.suse.com/show_bug.cgi?id=1228093


Reviewed-by: default avatarWayne Lin <wayne.lin@amd.com>
Signed-off-by: default avatarFangzhi Zuo <Jerry.Zuo@amd.com>
Signed-off-by: default avatarTom Chung <chiahsuan.chung@amd.com>
Tested-by: default avatarDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 12dbb3ed)
Cc: stable@vger.kernel.org
parent 0dbb81d4

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c

+24 −9
Original line number Diff line number Diff line
@@ -804,12 +804,25 @@ struct dsc_mst_fairness_params { 
};



#if defined(CONFIG_DRM_AMD_DC_FP)

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));

}
@@ -910,11 +923,12 @@ static int increase_dsc_bpp(struct drm_atomic_state *state, 
	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 {
@@ -1010,6 +1024,7 @@ static int try_disable_dsc(struct drm_atomic_state *state, 
	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
@@ -1039,7 +1054,7 @@ static int try_disable_dsc(struct drm_atomic_state *state, 
		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,
@@ -1052,8 +1067,7 @@ static int try_disable_dsc(struct drm_atomic_state *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);

			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,
@@ -1082,6 +1096,7 @@ static int compute_mst_dsc_configs_for_link(struct drm_atomic_state *state, 
	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));
@@ -1146,7 +1161,7 @@ static int compute_mst_dsc_configs_for_link(struct drm_atomic_state *state, 
	/* 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,
@@ -1165,7 +1180,7 @@ static int compute_mst_dsc_configs_for_link(struct drm_atomic_state *state, 
	/* 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,
@@ -1173,7 +1188,7 @@ static int compute_mst_dsc_configs_for_link(struct drm_atomic_state *state, 
			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,

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h

+3 −0
Original line number Diff line number Diff line
@@ -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



enum mst_msg_ready_type {

	NONE_MSG_RDY_EVENT = 0,

	DOWN_REP_MSG_RDY_EVENT = 1,