From: David Francis <david.fran...@amd.com>
We were using drm helpers to convert a timing into its
bandwidth, its bandwidth into pbn, and its pbn into timeslots
These helpers
-Did not take DSC timings into account
-Used the link rate and lane count of the link's aux device,
which are not the same as the link's current cap
-Did not take FEC into account (FEC reduces the PBN per timeslot)
For converting timing into PBN, use the new function
drm_dp_calc_pbn_mode_dsc that handles the DSC case
For converting PBN into time slots, amdgpu doesn't use the
'correct' atomic method (drm_dp_atomic_find_vcpi_slots), so
don't add a new helper to cover our approach. Use the same
means of calculating pbn per time slot as the DSC code.
Cc: Jerry Zuo <jerry....@amd.com>
Cc: Nicholas Kazlauskas <nicholas.kazlaus...@amd.com>
Signed-off-by: David Francis <david.fran...@amd.com>
---
.../amd/display/amdgpu_dm/amdgpu_dm_helpers.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
index b151a5a51a94..aaf3158534ab 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
@@ -188,8 +188,8 @@ bool dm_helpers_dp_mst_write_payload_allocation_table(
int slots = 0;
bool ret;
int clock;
- int bpp = 0;
int pbn = 0;
+ int pbn_per_timeslot, bpp = 0;
aconnector = (struct amdgpu_dm_connector *)stream->dm_stream_context;
@@ -233,11 +233,19 @@ bool dm_helpers_dp_mst_write_payload_allocation_table(
bpp = bpp * 3;
- /* TODO need to know link rate */
-
- pbn = drm_dp_calc_pbn_mode(clock, bpp, false);
+#ifdef CONFIG_DRM_AMD_DC_DSC_SUPPORT
+ if (stream->timing.flags.DSC)
+ pbn = drm_dp_calc_pbn_mode(clock,
+
stream->timing.dsc_cfg.bits_per_pixel,
+ true);
+ else
+#endif
+ pbn = drm_dp_calc_pbn_mode(clock, bpp, false);
- slots = drm_dp_find_vcpi_slots(mst_mgr, pbn);
+ /* Convert kilobits per second / 64 (for 64 timeslots) to pbn
(54/64 megabytes per second) */
+ pbn_per_timeslot = dc_link_bandwidth_kbps(
+ stream->link,
dc_link_get_link_cap(stream->link)) / (8 * 1000 * 54);
+ slots = DIV_ROUND_UP(pbn, pbn_per_timeslot);
ret = drm_dp_mst_allocate_vcpi(mst_mgr, mst_port, pbn, slots);
if (!ret)
--
2.17.1
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