On Thu, Nov 16, 2023 at 03:18:31PM +0200, Imre Deak wrote:
> On UHBR links the PBN divider is a fractional number, accordingly store
> it in fixed point format. For now drm_dp_get_vc_payload_bw() always
> returns a whole number and all callers will use only the integer part of
> it which should preserve the current behavior. The next patch will fix
> drm_dp_get_vc_payload_bw() for UHBR rates returning a fractional number
> for those (also accounting for the channel coding efficiency correctly).
>
> Cc: Lyude Paul <lyude@xxxxxxxxxx>
> Cc: Harry Wentland <harry.wentland@xxxxxxx>
> Cc: Alex Deucher <alexander.deucher@xxxxxxx>
> Cc: Wayne Lin <wayne.lin@xxxxxxx>
> Cc: amd-gfx@xxxxxxxxxxxxxxxxxxxxx
> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
> Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx>
> ---
> .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 5 +++--
> .../amd/display/amdgpu_dm/amdgpu_dm_helpers.c | 3 ++-
> .../display/amdgpu_dm/amdgpu_dm_mst_types.c | 5 +++--
> drivers/gpu/drm/display/drm_dp_mst_topology.c | 22 +++++++++++++------
> drivers/gpu/drm/i915/display/intel_dp_mst.c | 3 ++-
> drivers/gpu/drm/nouveau/dispnv50/disp.c | 6 +++--
> include/drm/display/drm_dp_mst_helper.h | 7 +++---
> 7 files changed, 33 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> index 74f9f02abcdec..12346b21d0b05 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -85,6 +85,7 @@
> #include <drm/drm_atomic_uapi.h>
> #include <drm/drm_atomic_helper.h>
> #include <drm/drm_blend.h>
> +#include <drm/drm_fixed.h>
> #include <drm/drm_fourcc.h>
> #include <drm/drm_edid.h>
> #include <drm/drm_eld.h>
> @@ -6909,8 +6910,8 @@ static int dm_encoder_helper_atomic_check(struct drm_encoder *encoder,
> if (IS_ERR(mst_state))
> return PTR_ERR(mst_state);
>
> - if (!mst_state->pbn_div)
> - mst_state->pbn_div = dm_mst_get_pbn_divider(aconnector->mst_root->dc_link);
> + if (!mst_state->pbn_div.full)
> + mst_state->pbn_div.full = dfixed_const(dm_mst_get_pbn_divider(aconnector->mst_root->dc_link));
Why doesn't that dfixed stuff return the correct type?
Anyways looks mostly mechanical
Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
>
> if (!state->duplicated) {
> int max_bpc = conn_state->max_requested_bpc;
> 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 ed784cf27d396..63024393b516e 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
> @@ -31,6 +31,7 @@
> #include <drm/drm_probe_helper.h>
> #include <drm/amdgpu_drm.h>
> #include <drm/drm_edid.h>
> +#include <drm/drm_fixed.h>
>
> #include "dm_services.h"
> #include "amdgpu.h"
> @@ -210,7 +211,7 @@ static void dm_helpers_construct_old_payload(
> struct drm_dp_mst_atomic_payload *old_payload)
> {
> struct drm_dp_mst_atomic_payload *pos;
> - int pbn_per_slot = mst_state->pbn_div;
> + int pbn_per_slot = dfixed_trunc(mst_state->pbn_div);
> u8 next_payload_vc_start = mgr->next_start_slot;
> u8 payload_vc_start = new_payload->vc_start_slot;
> u8 allocated_time_slots;
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> index 9a58e1a4c5f49..d1ba3ae228b08 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> @@ -27,6 +27,7 @@
> #include <drm/display/drm_dp_mst_helper.h>
> #include <drm/drm_atomic.h>
> #include <drm/drm_atomic_helper.h>
> +#include <drm/drm_fixed.h>
> #include "dm_services.h"
> #include "amdgpu.h"
> #include "amdgpu_dm.h"
> @@ -941,10 +942,10 @@ static int increase_dsc_bpp(struct drm_atomic_state *state,
> link_timeslots_used = 0;
>
> for (i = 0; i < count; i++)
> - link_timeslots_used += DIV_ROUND_UP(vars[i + k].pbn, mst_state->pbn_div);
> + link_timeslots_used += DIV_ROUND_UP(vars[i + k].pbn, dfixed_trunc(mst_state->pbn_div));
>
> fair_pbn_alloc =
> - (63 - link_timeslots_used) / remaining_to_increase * mst_state->pbn_div;
> + (63 - link_timeslots_used) / remaining_to_increase * dfixed_trunc(mst_state->pbn_div);
>
> if (initial_slack[next_index] > fair_pbn_alloc) {
> vars[next_index].pbn += fair_pbn_alloc;
> diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> index 4d72c9a32026e..000d05e80352a 100644
> --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> @@ -43,6 +43,7 @@
> #include <drm/drm_atomic_helper.h>
> #include <drm/drm_drv.h>
> #include <drm/drm_edid.h>
> +#include <drm/drm_fixed.h>
> #include <drm/drm_print.h>
> #include <drm/drm_probe_helper.h>
>
> @@ -3578,16 +3579,22 @@ static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr,
> * value is in units of PBNs/(timeslots/1 MTP). This value can be used to
> * convert the number of PBNs required for a given stream to the number of
> * timeslots this stream requires in each MTP.
> + *
> + * Returns the BW / timeslot value in 20.12 fixed point format.
> */
> -int drm_dp_get_vc_payload_bw(const struct drm_dp_mst_topology_mgr *mgr,
> - int link_rate, int link_lane_count)
> +fixed20_12 drm_dp_get_vc_payload_bw(const struct drm_dp_mst_topology_mgr *mgr,
> + int link_rate, int link_lane_count)
> {
> + fixed20_12 ret;
> +
> if (link_rate == 0 || link_lane_count == 0)
> drm_dbg_kms(mgr->dev, "invalid link rate/lane count: (%d / %d)\n",
> link_rate, link_lane_count);
>
> /* See DP v2.0 2.6.4.2, VCPayload_Bandwidth_for_OneTimeSlotPer_MTP_Allocation */
> - return link_rate * link_lane_count / 54000;
> + ret.full = dfixed_const(link_rate * link_lane_count / 54000);
> +
> + return ret;
> }
> EXPORT_SYMBOL(drm_dp_get_vc_payload_bw);
>
> @@ -4335,7 +4342,7 @@ int drm_dp_atomic_find_time_slots(struct drm_atomic_state *state,
> }
> }
>
> - req_slots = DIV_ROUND_UP(pbn, topology_state->pbn_div);
> + req_slots = DIV_ROUND_UP(pbn, dfixed_trunc(topology_state->pbn_div));
>
> drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] TU %d -> %d\n",
> port->connector->base.id, port->connector->name,
> @@ -4872,7 +4879,8 @@ void drm_dp_mst_dump_topology(struct seq_file *m,
> state = to_drm_dp_mst_topology_state(mgr->base.state);
> seq_printf(m, "\n*** Atomic state info ***\n");
> seq_printf(m, "payload_mask: %x, max_payloads: %d, start_slot: %u, pbn_div: %d\n",
> - state->payload_mask, mgr->max_payloads, state->start_slot, state->pbn_div);
> + state->payload_mask, mgr->max_payloads, state->start_slot,
> + dfixed_trunc(state->pbn_div));
>
> seq_printf(m, "\n| idx | port | vcpi | slots | pbn | dsc | status | sink name |\n");
> for (i = 0; i < mgr->max_payloads; i++) {
> @@ -5330,10 +5338,10 @@ drm_dp_mst_atomic_check_payload_alloc_limits(struct drm_dp_mst_topology_mgr *mgr
> }
>
> if (!payload_count)
> - mst_state->pbn_div = 0;
> + mst_state->pbn_div.full = dfixed_const(0);
>
> drm_dbg_atomic(mgr->dev, "[MST MGR:%p] mst state %p TU pbn_div=%d avail=%d used=%d\n",
> - mgr, mst_state, mst_state->pbn_div, avail_slots,
> + mgr, mst_state, dfixed_trunc(mst_state->pbn_div), avail_slots,
> mst_state->total_avail_slots - avail_slots);
>
> 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 0cb9405f59eaa..e5d6b811c22ef 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> @@ -26,6 +26,7 @@
> #include <drm/drm_atomic.h>
> #include <drm/drm_atomic_helper.h>
> #include <drm/drm_edid.h>
> +#include <drm/drm_fixed.h>
> #include <drm/drm_probe_helper.h>
>
> #include "i915_drv.h"
> @@ -202,7 +203,7 @@ static int intel_dp_mst_find_vcpi_slots_for_bpp(struct intel_encoder *encoder,
> */
> drm_WARN_ON(&i915->drm, remote_m_n.tu < crtc_state->dp_m_n.tu);
> crtc_state->dp_m_n.tu = remote_m_n.tu;
> - crtc_state->pbn = remote_m_n.tu * mst_state->pbn_div;
> + crtc_state->pbn = remote_m_n.tu * dfixed_trunc(mst_state->pbn_div);
>
> slots = drm_dp_atomic_find_time_slots(state, &intel_dp->mst_mgr,
> connector->port,
> diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> index 493fe4660f651..11fe75b68e95c 100644
> --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
> +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> @@ -40,6 +40,7 @@
> #include <drm/drm_edid.h>
> #include <drm/drm_eld.h>
> #include <drm/drm_fb_helper.h>
> +#include <drm/drm_fixed.h>
> #include <drm/drm_probe_helper.h>
> #include <drm/drm_vblank.h>
>
> @@ -946,7 +947,8 @@ nv50_msto_prepare(struct drm_atomic_state *state,
> if (ret == 0) {
> nvif_outp_dp_mst_vcpi(&mstm->outp->outp, msto->head->base.index,
> payload->vc_start_slot, payload->time_slots,
> - payload->pbn, payload->time_slots * mst_state->pbn_div);
> + payload->pbn,
> + payload->time_slots * dfixed_trunc(mst_state->pbn_div));
> } else {
> nvif_outp_dp_mst_vcpi(&mstm->outp->outp, msto->head->base.index, 0, 0, 0, 0);
> }
> @@ -990,7 +992,7 @@ nv50_msto_atomic_check(struct drm_encoder *encoder,
> if (IS_ERR(mst_state))
> return PTR_ERR(mst_state);
>
> - if (!mst_state->pbn_div) {
> + if (!mst_state->pbn_div.full) {
> struct nouveau_encoder *outp = mstc->mstm->outp;
>
> mst_state->pbn_div = drm_dp_get_vc_payload_bw(&mstm->mgr,
> diff --git a/include/drm/display/drm_dp_mst_helper.h b/include/drm/display/drm_dp_mst_helper.h
> index a4aad6df71f18..9b19d8bd520af 100644
> --- a/include/drm/display/drm_dp_mst_helper.h
> +++ b/include/drm/display/drm_dp_mst_helper.h
> @@ -25,6 +25,7 @@
> #include <linux/types.h>
> #include <drm/display/drm_dp_helper.h>
> #include <drm/drm_atomic.h>
> +#include <drm/drm_fixed.h>
>
> #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
> #include <linux/stackdepot.h>
> @@ -617,7 +618,7 @@ struct drm_dp_mst_topology_state {
> * @pbn_div: The current PBN divisor for this topology. The driver is expected to fill this
> * out itself.
> */
> - int pbn_div;
> + fixed20_12 pbn_div;
> };
>
> #define to_dp_mst_topology_mgr(x) container_of(x, struct drm_dp_mst_topology_mgr, base)
> @@ -839,8 +840,8 @@ struct edid *drm_dp_mst_get_edid(struct drm_connector *connector,
> struct drm_dp_mst_topology_mgr *mgr,
> struct drm_dp_mst_port *port);
>
> -int drm_dp_get_vc_payload_bw(const struct drm_dp_mst_topology_mgr *mgr,
> - int link_rate, int link_lane_count);
> +fixed20_12 drm_dp_get_vc_payload_bw(const struct drm_dp_mst_topology_mgr *mgr,
> + int link_rate, int link_lane_count);
>
> int drm_dp_calc_pbn_mode(int clock, int bpp);
>
> --
> 2.39.2
--
Ville Syrjälä
Intel
