From: Stanislav Lisovskiy <stanislav.lisovskiy@xxxxxxxxx>
Currently we seem to be using wrong DPCD register for reading compressed bpps,
reading min/max input bpc instead of compressed bpp.
Fix that, so that we now apply min/max compressed bpp limitations we get
from DP Spec Table 2-157 DP v2.0 and/or correspondent DPCD register
DP_DSC_MAX_BITS_PER_PIXEL_LOW/HIGH.
This might also allow us to get rid of an ugly compressed bpp recalculation,
which we had to add to make some MST hubs usable.
v2: - Fix operator precedence
v3: - Added debug info about compressed bpps
v4: - Don't try to intersect Sink input bpp and compressed bpps.
v5: - Decrease step while looking for suitable compressed bpp to
accommodate.
v6: - Use helper for getting min and max compressed_bpp (Ankit)
Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@xxxxxxxxx>
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_dp.c | 12 +++---
drivers/gpu/drm/i915/display/intel_dp.h | 4 ++
drivers/gpu/drm/i915/display/intel_dp_mst.c | 43 ++++++++-------------
3 files changed, 26 insertions(+), 33 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 32863bf7c016..be2b71fcb23f 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -1735,7 +1735,7 @@ u16 intel_dp_dsc_max_sink_compressed_bppx16(struct intel_dp *intel_dp,
return 0;
}
-static int dsc_sink_min_compressed_bpp(struct intel_crtc_state *pipe_config)
+int intel_dp_dsc_sink_min_compressed_bpp(struct intel_crtc_state *pipe_config)
{
/* From Mandatory bit rate range Support Table 2-157 (DP v2.0) */
switch (pipe_config->output_format) {
@@ -1752,9 +1752,9 @@ static int dsc_sink_min_compressed_bpp(struct intel_crtc_state *pipe_config)
return 0;
}
-static int dsc_sink_max_compressed_bpp(struct intel_dp *intel_dp,
- struct intel_crtc_state *pipe_config,
- int bpc)
+int intel_dp_dsc_sink_max_compressed_bpp(struct intel_dp *intel_dp,
+ struct intel_crtc_state *pipe_config,
+ int bpc)
{
return intel_dp_dsc_max_sink_compressed_bppx16(intel_dp,
pipe_config, bpc) >> 4;
@@ -1792,11 +1792,11 @@ static int dsc_compute_compressed_bpp(struct intel_dp *intel_dp,
int ret;
dsc_src_min_bpp = dsc_src_min_compressed_bpp();
- dsc_sink_min_bpp = dsc_sink_min_compressed_bpp(pipe_config);
+ dsc_sink_min_bpp = intel_dp_dsc_sink_min_compressed_bpp(pipe_config);
dsc_min_bpp = max(dsc_src_min_bpp, dsc_sink_min_bpp);
dsc_src_max_bpp = dsc_src_max_compressed_bpp(intel_dp);
- dsc_sink_max_bpp = dsc_sink_max_compressed_bpp(intel_dp, pipe_config, pipe_bpp / 3);
+ dsc_sink_max_bpp = intel_dp_dsc_sink_max_compressed_bpp(intel_dp, pipe_config, pipe_bpp / 3);
dsc_max_bpp = dsc_sink_max_bpp ? min(dsc_sink_max_bpp, dsc_src_max_bpp) : dsc_src_max_bpp;
/* Compressed BPP should be less than the Input DSC bpp */
diff --git a/drivers/gpu/drm/i915/display/intel_dp.h b/drivers/gpu/drm/i915/display/intel_dp.h
index 4d3bc867316e..7f088779ded5 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.h
+++ b/drivers/gpu/drm/i915/display/intel_dp.h
@@ -113,6 +113,10 @@ u16 intel_dp_dsc_get_max_compressed_bpp(struct drm_i915_private *i915,
enum intel_output_format output_format,
u32 pipe_bpp,
u32 timeslots);
+int intel_dp_dsc_sink_min_compressed_bpp(struct intel_crtc_state *pipe_config);
+int intel_dp_dsc_sink_max_compressed_bpp(struct intel_dp *intel_dp,
+ struct intel_crtc_state *pipe_config,
+ int bpc);
u8 intel_dp_dsc_get_slice_count(struct intel_dp *intel_dp,
int mode_clock, int mode_hdisplay,
bool bigjoiner);
diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index 64a2168b5732..8c3613796973 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -101,6 +101,9 @@ static int intel_dp_mst_find_vcpi_slots_for_bpp(struct intel_encoder *encoder,
crtc_state->lane_count);
}
+ drm_dbg_kms(&i915->drm, "Looking for slots in range min bpp %d max bpp %d\n",
+ min_bpp, max_bpp);
+
for (bpp = max_bpp; bpp >= min_bpp; bpp -= step) {
drm_dbg_kms(&i915->drm, "Trying bpp %d\n", bpp);
@@ -194,8 +197,7 @@ static int intel_dp_dsc_mst_compute_link_config(struct intel_encoder *encoder,
u8 dsc_bpc[3] = {0};
int min_bpp, max_bpp, sink_min_bpp, sink_max_bpp;
u8 dsc_max_bpc;
- bool need_timeslot_recalc = false;
- u32 last_compressed_bpp;
+ int min_compressed_bpp, max_compressed_bpp;
/* Max DSC Input BPC for ICL is 10 and for TGL+ is 12 */
if (DISPLAY_VER(i915) >= 12)
@@ -231,34 +233,21 @@ static int intel_dp_dsc_mst_compute_link_config(struct intel_encoder *encoder,
if (max_bpp > sink_max_bpp)
max_bpp = sink_max_bpp;
- slots = intel_dp_mst_find_vcpi_slots_for_bpp(encoder, crtc_state, max_bpp,
- min_bpp, limits,
- conn_state, 2 * 3, true);
-
- if (slots < 0)
- return slots;
-
- last_compressed_bpp = crtc_state->dsc.compressed_bpp;
+ max_compressed_bpp = intel_dp_dsc_sink_max_compressed_bpp(intel_dp, crtc_state, max_bpp / 3);
+ min_compressed_bpp = intel_dp_dsc_sink_min_compressed_bpp(crtc_state);
+ drm_dbg_kms(&i915->drm, "DSC Sink supported compressed min bpp %d compressed max bpp %d\n",
+ min_compressed_bpp, max_compressed_bpp);
- crtc_state->dsc.compressed_bpp = intel_dp_dsc_nearest_valid_bpp(i915,
- last_compressed_bpp,
- crtc_state->pipe_bpp);
+ /* Align compressed bpps according to our own constraints */
+ max_compressed_bpp = intel_dp_dsc_nearest_valid_bpp(i915, max_compressed_bpp, crtc_state->pipe_bpp);
+ min_compressed_bpp = intel_dp_dsc_nearest_valid_bpp(i915, min_compressed_bpp, crtc_state->pipe_bpp);
- if (crtc_state->dsc.compressed_bpp != last_compressed_bpp)
- need_timeslot_recalc = true;
+ slots = intel_dp_mst_find_vcpi_slots_for_bpp(encoder, crtc_state, max_compressed_bpp,
+ min_compressed_bpp, limits,
+ conn_state, 1, true);
- /*
- * Apparently some MST hubs dislike if vcpi slots are not matching precisely
- * the actual compressed bpp we use.
- */
- if (need_timeslot_recalc) {
- slots = intel_dp_mst_find_vcpi_slots_for_bpp(encoder, crtc_state,
- crtc_state->dsc.compressed_bpp,
- crtc_state->dsc.compressed_bpp,
- limits, conn_state, 2 * 3, true);
- if (slots < 0)
- return slots;
- }
+ if (slots < 0)
+ return slots;
intel_link_compute_m_n(crtc_state->dsc.compressed_bpp,
crtc_state->lane_count,
--
2.25.1
