> -----Original Message-----
> From: Nautiyal, Ankit K <ankit.k.nautiyal@xxxxxxxxx>
> Sent: Friday, November 10, 2023 3:40 PM
> To: dri-devel@xxxxxxxxxxxxxxxxxxxxx; intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> Cc: Sharma, Swati2 <swati2.sharma@xxxxxxxxx>; Kulkarni, Vandita
> <vandita.kulkarni@xxxxxxxxx>; Kandpal, Suraj <suraj.kandpal@xxxxxxxxx>;
> suijingfeng@xxxxxxxxxxx
> Subject: [PATCH 09/11] drm/i915/dp_mst: Use precision of 1/16 for computing
> bpp
>
> Modify the functions to deal with bpps with 1/16 precision.
> This will make way for cases when DSC with fractional bpp is used.
> For bpp without DSC, there is no change, as we still use whole numbers.
>
LGTM.
Reviewed-by: Suraj Kandpal <suraj.kandpal@xxxxxxxxx>
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/intel_dp_mst.c | 56 +++++++++++----------
> 1 file changed, 30 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> index 5c7e9d296483..e7806fe11b9d 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> @@ -47,20 +47,21 @@
> #include "intel_vdsc.h"
> #include "skl_scaler.h"
>
> -static int intel_dp_mst_check_constraints(struct drm_i915_private *i915, int
> bpp,
> +static int intel_dp_mst_check_constraints(struct drm_i915_private
> +*i915, int bpp_x16,
> const struct drm_display_mode
> *adjusted_mode,
> struct intel_crtc_state *crtc_state,
> bool dsc)
> {
> if (intel_dp_is_uhbr(crtc_state) && DISPLAY_VER(i915) <= 13 && dsc) {
> - int output_bpp = bpp;
> + int output_bpp_x16 = bpp_x16;
> /* DisplayPort 2 128b/132b, bits per lane is always 32 */
> int symbol_clock = crtc_state->port_clock / 32;
>
> - if (output_bpp * adjusted_mode->crtc_clock >=
> + if (DIV_ROUND_UP(output_bpp_x16 * adjusted_mode-
> >crtc_clock, 16) >=
> symbol_clock * 72) {
> drm_dbg_kms(&i915->drm, "UHBR check
> failed(required bw %d available %d)\n",
> - output_bpp * adjusted_mode->crtc_clock,
> symbol_clock * 72);
> + DIV_ROUND_UP(output_bpp_x16 *
> adjusted_mode->crtc_clock, 16),
> + symbol_clock * 72);
> return -EINVAL;
> }
> }
> @@ -127,8 +128,8 @@ static void intel_dp_mst_compute_m_n(const struct
> intel_crtc_state *crtc_state,
>
> static int intel_dp_mst_find_vcpi_slots_for_bpp(struct intel_encoder
> *encoder,
> struct intel_crtc_state
> *crtc_state,
> - int max_bpp,
> - int min_bpp,
> + int max_bpp_x16,
> + int min_bpp_x16,
> struct link_config_limits
> *limits,
> struct drm_connector_state
> *conn_state,
> int step,
> @@ -143,7 +144,7 @@ static int intel_dp_mst_find_vcpi_slots_for_bpp(struct
> intel_encoder *encoder,
> struct drm_i915_private *i915 = to_i915(connector->base.dev);
> const struct drm_display_mode *adjusted_mode =
> &crtc_state->hw.adjusted_mode;
> - int bpp, slots = -EINVAL;
> + int bpp_x16, slots = -EINVAL;
> int ret = 0;
>
> mst_state = drm_atomic_get_mst_topology_state(state, &intel_dp-
> >mst_mgr); @@ -164,25 +165,25 @@ static int
> intel_dp_mst_find_vcpi_slots_for_bpp(struct intel_encoder *encoder,
> crtc_state->port_clock,
> 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);
> + drm_dbg_kms(&i915->drm, "Looking for slots in range min bpp "
> BPP_X16_FMT " max bpp " BPP_X16_FMT "\n",
> + BPP_X16_ARGS(min_bpp_x16),
> BPP_X16_ARGS(max_bpp_x16));
>
> - for (bpp = max_bpp; bpp >= min_bpp; bpp -= step) {
> + for (bpp_x16 = max_bpp_x16; bpp_x16 >= min_bpp_x16; bpp_x16 -=
> step) {
> struct intel_link_m_n remote_m_n;
> - int link_bpp;
> + int link_bpp_x16;
>
> - drm_dbg_kms(&i915->drm, "Trying bpp %d\n", bpp);
> + drm_dbg_kms(&i915->drm, "Trying bpp " BPP_X16_FMT "\n",
> +BPP_X16_ARGS(bpp_x16));
>
> - ret = intel_dp_mst_check_constraints(i915, bpp,
> adjusted_mode, crtc_state, dsc);
> + ret = intel_dp_mst_check_constraints(i915, bpp_x16,
> adjusted_mode,
> +crtc_state, dsc);
> if (ret)
> continue;
>
> - link_bpp = dsc ? bpp :
> - intel_dp_output_bpp(crtc_state->output_format,
> bpp);
> + link_bpp_x16 = dsc ? bpp_x16 :
> + intel_dp_output_bpp(crtc_state->output_format,
> to_bpp_int(bpp_x16));
>
> - intel_dp_mst_compute_m_n(crtc_state, connector, false, dsc,
> to_bpp_x16(link_bpp),
> + intel_dp_mst_compute_m_n(crtc_state, connector, false, dsc,
> +link_bpp_x16,
> &crtc_state->dp_m_n);
> - intel_dp_mst_compute_m_n(crtc_state, connector, true, dsc,
> to_bpp_x16(link_bpp),
> + intel_dp_mst_compute_m_n(crtc_state, connector, true, dsc,
> +link_bpp_x16,
> &remote_m_n);
>
> /*
> @@ -225,10 +226,11 @@ static int
> intel_dp_mst_find_vcpi_slots_for_bpp(struct intel_encoder *encoder,
> slots);
> } else {
> if (!dsc)
> - crtc_state->pipe_bpp = bpp;
> + crtc_state->pipe_bpp = to_bpp_int(bpp_x16);
> else
> - crtc_state->dsc.compressed_bpp_x16 =
> to_bpp_x16(bpp);
> - drm_dbg_kms(&i915->drm, "Got %d slots for pipe bpp %d dsc
> %d\n", slots, bpp, dsc);
> + crtc_state->dsc.compressed_bpp_x16 = bpp_x16;
> + drm_dbg_kms(&i915->drm, "Got %d slots for pipe bpp "
> BPP_X16_FMT " dsc %d\n",
> + slots, BPP_X16_ARGS(bpp_x16), dsc);
> }
>
> return slots;
> @@ -246,10 +248,10 @@ static int intel_dp_mst_compute_link_config(struct
> intel_encoder *encoder,
> * YUV420 is only half of the pipe bpp value.
> */
> slots = intel_dp_mst_find_vcpi_slots_for_bpp(encoder, crtc_state,
> - to_bpp_int(limits-
> >link.max_bpp_x16),
> - to_bpp_int(limits-
> >link.min_bpp_x16),
> + limits->link.max_bpp_x16,
> + limits->link.min_bpp_x16,
> limits,
> - conn_state, 2 * 3, false);
> + conn_state, 2 * 3 * 16,
> false);
>
> if (slots < 0)
> return slots;
> @@ -325,9 +327,11 @@ static int
> intel_dp_dsc_mst_compute_link_config(struct intel_encoder *encoder,
> min_compressed_bpp = intel_dp_dsc_nearest_valid_bpp(i915,
> min_compressed_bpp,
> crtc_state-
> >pipe_bpp);
>
> - slots = intel_dp_mst_find_vcpi_slots_for_bpp(encoder, crtc_state,
> max_compressed_bpp,
> - min_compressed_bpp,
> limits,
> - conn_state, 1, true);
> + slots = intel_dp_mst_find_vcpi_slots_for_bpp(encoder, crtc_state,
> +
> to_bpp_x16(max_compressed_bpp),
> +
> to_bpp_x16(min_compressed_bpp),
> + limits,
> + conn_state, 16, true);
>
> if (slots < 0)
> return slots;
> --
> 2.40.1
