[PATCH 15/29] drm/i915/dp: Use drm_dp_max_dprx_data_rate()
Imre Deak
imre.deak at intel.com
Wed Dec 20 00:53:54 UTC 2023
Signed-off-by: Imre Deak <imre.deak at intel.com>
---
drivers/gpu/drm/i915/display/intel_display.c | 2 +-
drivers/gpu/drm/i915/display/intel_dp.c | 62 +++-----------------
drivers/gpu/drm/i915/display/intel_dp_mst.c | 2 +-
3 files changed, 10 insertions(+), 56 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index be267ccb1b9d4..132b240d6c8bb 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -2477,7 +2477,7 @@ intel_link_compute_m_n(u16 bits_per_pixel_x16, int nlanes,
u32 link_symbol_clock = intel_dp_link_symbol_clock(link_clock);
u32 data_m = intel_dp_effective_data_rate(pixel_clock, bits_per_pixel_x16,
bw_overhead);
- u32 data_n = intel_dp_max_data_rate(link_clock, nlanes);
+ u32 data_n = drm_dp_max_dprx_data_rate(link_clock, nlanes);
/*
* Windows/BIOS uses fixed M/N values always. Follow suit.
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 9201623a4a3d9..49ee27f938399 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -382,52 +382,6 @@ int intel_dp_effective_data_rate(int pixel_clock, int bpp_x16,
1000000 * 16 * 8);
}
-/*
- * Given a link rate and lanes, get the data bandwidth.
- *
- * Data bandwidth is the actual payload rate, which depends on the data
- * bandwidth efficiency and the link rate.
- *
- * For 8b/10b channel encoding, SST and non-FEC, the data bandwidth efficiency
- * is 80%. For example, for a 1.62 Gbps link, 1.62*10^9 bps * 0.80 * (1/8) =
- * 162000 kBps. With 8-bit symbols, we have 162000 kHz symbol clock. Just by
- * coincidence, the port clock in kHz matches the data bandwidth in kBps, and
- * they equal the link bit rate in Gbps multiplied by 100000. (Note that this no
- * longer holds for data bandwidth as soon as FEC or MST is taken into account!)
- *
- * For 128b/132b channel encoding, the data bandwidth efficiency is 96.71%. For
- * example, for a 10 Gbps link, 10*10^9 bps * 0.9671 * (1/8) = 1208875
- * kBps. With 32-bit symbols, we have 312500 kHz symbol clock. The value 1000000
- * does not match the symbol clock, the port clock (not even if you think in
- * terms of a byte clock), nor the data bandwidth. It only matches the link bit
- * rate in units of 10000 bps.
- */
-int
-intel_dp_max_data_rate(int max_link_rate, int max_lanes)
-{
- int ch_coding_efficiency =
- drm_dp_bw_channel_coding_efficiency(drm_dp_is_uhbr_rate(max_link_rate));
- int max_link_rate_kbps = max_link_rate * 10;
-
- /*
- * UHBR rates always use 128b/132b channel encoding, and have
- * 97.71% data bandwidth efficiency. Consider max_link_rate the
- * link bit rate in units of 10000 bps.
- */
- /*
- * Lower than UHBR rates always use 8b/10b channel encoding, and have
- * 80% data bandwidth efficiency for SST non-FEC. However, this turns
- * out to be a nop by coincidence:
- *
- * int max_link_rate_kbps = max_link_rate * 10;
- * max_link_rate_kbps = DIV_ROUND_DOWN_ULL(max_link_rate_kbps * 8, 10);
- * max_link_rate = max_link_rate_kbps / 8;
- */
- return DIV_ROUND_DOWN_ULL(mul_u32_u32(max_link_rate_kbps * max_lanes,
- ch_coding_efficiency),
- 1000000 * 8);
-}
-
bool intel_dp_can_bigjoiner(struct intel_dp *intel_dp)
{
struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
@@ -657,7 +611,7 @@ static bool intel_dp_can_link_train_fallback_for_edp(struct intel_dp *intel_dp,
int mode_rate, max_rate;
mode_rate = intel_dp_link_required(fixed_mode->clock, 18);
- max_rate = intel_dp_max_data_rate(link_rate, lane_count);
+ max_rate = drm_dp_max_dprx_data_rate(link_rate, lane_count);
if (mode_rate > max_rate)
return false;
@@ -1259,7 +1213,7 @@ intel_dp_mode_valid(struct drm_connector *_connector,
max_link_clock = intel_dp_max_link_rate(intel_dp);
max_lanes = intel_dp_max_lane_count(intel_dp);
- max_rate = intel_dp_max_data_rate(max_link_clock, max_lanes);
+ max_rate = drm_dp_max_dprx_data_rate(max_link_clock, max_lanes);
mode_rate = intel_dp_link_required(target_clock,
intel_dp_mode_min_output_bpp(connector, mode));
@@ -1609,8 +1563,8 @@ intel_dp_compute_link_config_wide(struct intel_dp *intel_dp,
for (lane_count = limits->min_lane_count;
lane_count <= limits->max_lane_count;
lane_count <<= 1) {
- link_avail = intel_dp_max_data_rate(link_rate,
- lane_count);
+ link_avail = drm_dp_max_dprx_data_rate(link_rate,
+ lane_count);
if (mode_rate <= link_avail) {
pipe_config->lane_count = lane_count;
@@ -2461,8 +2415,8 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
"DP link rate required %i available %i\n",
intel_dp_link_required(adjusted_mode->crtc_clock,
to_bpp_int_roundup(pipe_config->dsc.compressed_bpp_x16)),
- intel_dp_max_data_rate(pipe_config->port_clock,
- pipe_config->lane_count));
+ drm_dp_max_dprx_data_rate(pipe_config->port_clock,
+ pipe_config->lane_count));
} else {
drm_dbg_kms(&i915->drm, "DP lane count %d clock %d bpp %d\n",
pipe_config->lane_count, pipe_config->port_clock,
@@ -2472,8 +2426,8 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
"DP link rate required %i available %i\n",
intel_dp_link_required(adjusted_mode->crtc_clock,
pipe_config->pipe_bpp),
- intel_dp_max_data_rate(pipe_config->port_clock,
- pipe_config->lane_count));
+ drm_dp_max_dprx_data_rate(pipe_config->port_clock,
+ pipe_config->lane_count));
}
return 0;
}
diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index cad57ee44f6fb..e21df73aa2405 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -1294,7 +1294,7 @@ intel_dp_mst_mode_valid_ctx(struct drm_connector *connector,
max_link_clock = intel_dp_max_link_rate(intel_dp);
max_lanes = intel_dp_max_lane_count(intel_dp);
- max_rate = intel_dp_max_data_rate(max_link_clock, max_lanes);
+ max_rate = drm_dp_max_dprx_data_rate(max_link_clock, max_lanes);
mode_rate = intel_dp_link_required(mode->clock, min_bpp);
ret = drm_modeset_lock(&mgr->base.lock, ctx);
--
2.39.2
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