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drm/amd/display: expose dsc overhead bw in dc dsc header
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[why]
DM needs to know how much overhead is added to DSC as result
of AMD internal DSC limitation.

Acked-by: Mikita Lipski <mikita.lipski@amd.com>
Signed-off-by: Wenjing Liu <wenjing.liu@amd.com>
Reviewed-by: George Shen <george.shen@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
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Wenjing Liu authored and Alex Deucher committed Sep 14, 2021
1 parent e312af6 commit b25715a
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Showing 2 changed files with 37 additions and 37 deletions.
5 changes: 5 additions & 0 deletions drivers/gpu/drm/amd/display/dc/dc_dsc.h
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Original file line number Diff line number Diff line change
Expand Up @@ -81,6 +81,11 @@ bool dc_dsc_compute_config(
uint32_t dc_dsc_stream_bandwidth_in_kbps(const struct dc_crtc_timing *timing,
uint32_t bpp_x16, uint32_t num_slices_h, bool is_dp);

uint32_t dc_dsc_stream_bandwidth_overhead_in_kbps(
const struct dc_crtc_timing *timing,
const int num_slices_h,
const bool is_dp);

void dc_dsc_get_policy_for_timing(const struct dc_crtc_timing *timing,
uint32_t max_target_bpp_limit_override_x16,
struct dc_dsc_policy *policy);
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69 changes: 32 additions & 37 deletions drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -76,11 +76,6 @@ static bool setup_dsc_config(
int max_dsc_target_bpp_limit_override_x16,
struct dc_dsc_config *dsc_cfg);

static struct fixed31_32 compute_dsc_max_bandwidth_overhead(
const struct dc_crtc_timing *timing,
const int num_slices_h,
const bool is_dp);

static bool dsc_buff_block_size_from_dpcd(int dpcd_buff_block_size, int *buff_block_size)
{

Expand Down Expand Up @@ -462,47 +457,21 @@ static inline uint32_t dsc_div_by_10_round_up(uint32_t value)
return (value + 9) / 10;
}

static struct fixed31_32 compute_dsc_max_bandwidth_overhead(
const struct dc_crtc_timing *timing,
const int num_slices_h,
const bool is_dp)
{
struct fixed31_32 max_dsc_overhead;
struct fixed31_32 refresh_rate;

if (dsc_policy_disable_dsc_stream_overhead || !is_dp)
return dc_fixpt_from_int(0);

/* use target bpp that can take entire target bandwidth */
refresh_rate = dc_fixpt_from_int(timing->pix_clk_100hz);
refresh_rate = dc_fixpt_div_int(refresh_rate, timing->h_total);
refresh_rate = dc_fixpt_div_int(refresh_rate, timing->v_total);
refresh_rate = dc_fixpt_mul_int(refresh_rate, 100);

max_dsc_overhead = dc_fixpt_from_int(num_slices_h);
max_dsc_overhead = dc_fixpt_mul_int(max_dsc_overhead, timing->v_total);
max_dsc_overhead = dc_fixpt_mul_int(max_dsc_overhead, 256);
max_dsc_overhead = dc_fixpt_div_int(max_dsc_overhead, 1000);
max_dsc_overhead = dc_fixpt_mul(max_dsc_overhead, refresh_rate);

return max_dsc_overhead;
}

static uint32_t compute_bpp_x16_from_target_bandwidth(
const uint32_t bandwidth_in_kbps,
const struct dc_crtc_timing *timing,
const uint32_t num_slices_h,
const uint32_t bpp_increment_div,
const bool is_dp)
{
struct fixed31_32 overhead_in_kbps;
uint32_t overhead_in_kbps;
struct fixed31_32 effective_bandwidth_in_kbps;
struct fixed31_32 bpp_x16;

overhead_in_kbps = compute_dsc_max_bandwidth_overhead(
overhead_in_kbps = dc_dsc_stream_bandwidth_overhead_in_kbps(
timing, num_slices_h, is_dp);
effective_bandwidth_in_kbps = dc_fixpt_from_int(bandwidth_in_kbps);
effective_bandwidth_in_kbps = dc_fixpt_sub(effective_bandwidth_in_kbps,
effective_bandwidth_in_kbps = dc_fixpt_sub_int(effective_bandwidth_in_kbps,
overhead_in_kbps);
bpp_x16 = dc_fixpt_mul_int(effective_bandwidth_in_kbps, 10);
bpp_x16 = dc_fixpt_div_int(bpp_x16, timing->pix_clk_100hz);
Expand Down Expand Up @@ -994,19 +963,45 @@ bool dc_dsc_compute_config(
uint32_t dc_dsc_stream_bandwidth_in_kbps(const struct dc_crtc_timing *timing,
uint32_t bpp_x16, uint32_t num_slices_h, bool is_dp)
{
struct fixed31_32 overhead_in_kbps;
uint32_t overhead_in_kbps;
struct fixed31_32 bpp;
struct fixed31_32 actual_bandwidth_in_kbps;

overhead_in_kbps = compute_dsc_max_bandwidth_overhead(
overhead_in_kbps = dc_dsc_stream_bandwidth_overhead_in_kbps(
timing, num_slices_h, is_dp);
bpp = dc_fixpt_from_fraction(bpp_x16, 16);
actual_bandwidth_in_kbps = dc_fixpt_from_fraction(timing->pix_clk_100hz, 10);
actual_bandwidth_in_kbps = dc_fixpt_mul(actual_bandwidth_in_kbps, bpp);
actual_bandwidth_in_kbps = dc_fixpt_add(actual_bandwidth_in_kbps, overhead_in_kbps);
actual_bandwidth_in_kbps = dc_fixpt_add_int(actual_bandwidth_in_kbps, overhead_in_kbps);
return dc_fixpt_ceil(actual_bandwidth_in_kbps);
}

uint32_t dc_dsc_stream_bandwidth_overhead_in_kbps(
const struct dc_crtc_timing *timing,
const int num_slices_h,
const bool is_dp)
{
struct fixed31_32 max_dsc_overhead;
struct fixed31_32 refresh_rate;

if (dsc_policy_disable_dsc_stream_overhead || !is_dp)
return 0;

/* use target bpp that can take entire target bandwidth */
refresh_rate = dc_fixpt_from_int(timing->pix_clk_100hz);
refresh_rate = dc_fixpt_div_int(refresh_rate, timing->h_total);
refresh_rate = dc_fixpt_div_int(refresh_rate, timing->v_total);
refresh_rate = dc_fixpt_mul_int(refresh_rate, 100);

max_dsc_overhead = dc_fixpt_from_int(num_slices_h);
max_dsc_overhead = dc_fixpt_mul_int(max_dsc_overhead, timing->v_total);
max_dsc_overhead = dc_fixpt_mul_int(max_dsc_overhead, 256);
max_dsc_overhead = dc_fixpt_div_int(max_dsc_overhead, 1000);
max_dsc_overhead = dc_fixpt_mul(max_dsc_overhead, refresh_rate);

return dc_fixpt_ceil(max_dsc_overhead);
}

void dc_dsc_get_policy_for_timing(const struct dc_crtc_timing *timing,
uint32_t max_target_bpp_limit_override_x16,
struct dc_dsc_policy *policy)
Expand Down

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