[PATCH] drm/amd/display: Fix mst hub unplug warning

[Alex Deucher]

On Thu, Oct 5, 2023 at 4:04 AM Wayne Lin <Wayne.Lin at amd.com> wrote:
>
> [Why]
> Unplug mst hub will cause warning. That's because
> dm_helpers_construct_old_payload() is changed to be called after
> payload removement from dc link.
>
> In dm_helpers_construct_old_payload(), We refer to the vcpi in
> payload allocation table of dc link to construct the old payload
> and payload is no longer in the table when we call the function
> now.
>
> [How]
> Refer to the mst_state to construct the number of time slot for old
> payload now. Note that dm_helpers_construct_old_payload() is just
> a quick workaround before and we are going to abandon it soon.
>
> Fixes: 5aa1dfcdf0a4 ("drm/mst: Refactor the flow for payload allocation/removement")
> Reviewed-by: Jerry Zuo <jerry.zuo at amd.com>
> Signed-off-by: Wayne Lin <Wayne.Lin at amd.com>

Pushed to drm-misc-next.  Thanks!

Alex

> ---
>  .../amd/display/amdgpu_dm/amdgpu_dm_helpers.c | 38 +++++++++----------
>  1 file changed, 18 insertions(+), 20 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 baf7e5254fb3..2f94bcf128c0 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
> @@ -204,15 +204,16 @@ void dm_helpers_dp_update_branch_info(
>  {}
>
>  static void dm_helpers_construct_old_payload(
> -                       struct dc_link *link,
> -                       int pbn_per_slot,
> +                       struct drm_dp_mst_topology_mgr *mgr,
> +                       struct drm_dp_mst_topology_state *mst_state,
>                         struct drm_dp_mst_atomic_payload *new_payload,
>                         struct drm_dp_mst_atomic_payload *old_payload)
>  {
> -       struct link_mst_stream_allocation_table current_link_table =
> -                                                                       link->mst_stream_alloc_table;
> -       struct link_mst_stream_allocation *dc_alloc;
> -       int i;
> +       struct drm_dp_mst_atomic_payload *pos;
> +       int pbn_per_slot = 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;
>
>         *old_payload = *new_payload;
>
> @@ -221,20 +222,17 @@ static void dm_helpers_construct_old_payload(
>          * struct drm_dp_mst_atomic_payload are don't care fields
>          * while calling drm_dp_remove_payload_part2()
>          */
> -       for (i = 0; i < current_link_table.stream_count; i++) {
> -               dc_alloc =
> -                       &current_link_table.stream_allocations[i];
> -
> -               if (dc_alloc->vcp_id == new_payload->vcpi) {
> -                       old_payload->time_slots = dc_alloc->slot_count;
> -                       old_payload->pbn = dc_alloc->slot_count * pbn_per_slot;
> -                       break;
> -               }
> +       list_for_each_entry(pos, &mst_state->payloads, next) {
> +               if (pos != new_payload &&
> +                   pos->vc_start_slot > payload_vc_start &&
> +                   pos->vc_start_slot < next_payload_vc_start)
> +                       next_payload_vc_start = pos->vc_start_slot;
>         }
>
> -       /* make sure there is an old payload*/
> -       ASSERT(i != current_link_table.stream_count);
> +       allocated_time_slots = next_payload_vc_start - payload_vc_start;
>
> +       old_payload->time_slots = allocated_time_slots;
> +       old_payload->pbn = allocated_time_slots * pbn_per_slot;
>  }
>
>  /*
> @@ -272,8 +270,8 @@ bool dm_helpers_dp_mst_write_payload_allocation_table(
>                 drm_dp_add_payload_part1(mst_mgr, mst_state, new_payload);
>         } else {
>                 /* construct old payload by VCPI*/
> -               dm_helpers_construct_old_payload(stream->link, mst_state->pbn_div,
> -                                               new_payload, &old_payload);
> +               dm_helpers_construct_old_payload(mst_mgr, mst_state,
> +                                                new_payload, &old_payload);
>                 target_payload = &old_payload;
>
>                 drm_dp_remove_payload_part1(mst_mgr, mst_state, new_payload);
> @@ -366,7 +364,7 @@ bool dm_helpers_dp_mst_send_payload_allocation(
>         if (enable) {
>                 ret = drm_dp_add_payload_part2(mst_mgr, mst_state->base.state, new_payload);
>         } else {
> -               dm_helpers_construct_old_payload(stream->link, mst_state->pbn_div,
> +               dm_helpers_construct_old_payload(mst_mgr, mst_state,
>                                                  new_payload, &old_payload);
>                 drm_dp_remove_payload_part2(mst_mgr, mst_state, &old_payload, new_payload);
>         }
> --
> 2.37.3
>