On Fri, 2019-08-23 at 16:28 -0400, David Francis wrote:
> With DSC, bpp can be fractional in multiples of 1/16.
>
> Change drm_dp_calc_pbn_mode to reflect this, adding a new
> parameter bool dsc. When this parameter is true, treat the
> bpp parameter as having units not of bits per pixel, but
> 1/16 of a bit per pixel
>
> v2: Don't add separate function for this
>
> Cc: Lyude Paul <lyude@xxxxxxxxxx>
> Signed-off-by: David Francis <David.Francis@xxxxxxx>
> ---
> .../amd/display/amdgpu_dm/amdgpu_dm_helpers.c | 2 +-
> drivers/gpu/drm/drm_dp_mst_topology.c | 16 ++++++++++++----
> drivers/gpu/drm/i915/display/intel_dp_mst.c | 2 +-
> drivers/gpu/drm/nouveau/dispnv50/disp.c | 2 +-
> drivers/gpu/drm/radeon/radeon_dp_mst.c | 2 +-
> include/drm/drm_dp_mst_helper.h | 3 +--
> 6 files changed, 17 insertions(+), 10 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 a0ed0154a9f0..abafb5221b44 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
> @@ -235,7 +235,7 @@ bool dm_helpers_dp_mst_write_payload_allocation_table(
>
> /* TODO need to know link rate */
>
> - pbn = drm_dp_calc_pbn_mode(clock, bpp);
> + pbn = drm_dp_calc_pbn_mode(clock, bpp, false);
>
> slots = drm_dp_find_vcpi_slots(mst_mgr, pbn);
> ret = drm_dp_mst_allocate_vcpi(mst_mgr, mst_port, pbn, slots);
> diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c
> b/drivers/gpu/drm/drm_dp_mst_topology.c
> index 82add736e17d..157ffa30d984 100644
> --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> @@ -3534,10 +3534,11 @@ EXPORT_SYMBOL(drm_dp_check_act_status);
> * drm_dp_calc_pbn_mode() - Calculate the PBN for a mode.
> * @clock: dot clock for the mode
> * @bpp: bpp for the mode.
> + * @dsc: DSC mode. If true, bpp has units of 1/16 of a bit per pixel
> *
> * This uses the formula in the spec to calculate the PBN value for a mode.
> */
> -int drm_dp_calc_pbn_mode(int clock, int bpp)
> +int drm_dp_calc_pbn_mode(int clock, int bpp, bool dsc)
> {
> u64 kbps;
> s64 peak_kbps;
> @@ -3555,11 +3556,18 @@ int drm_dp_calc_pbn_mode(int clock, int bpp)
> * peak_kbps *= (1006/1000)
> * peak_kbps *= (64/54)
> * peak_kbps *= 8 convert to bytes
> + *
> + * If the bpp is in units of 1/16, further divide by 16. Put this
> + * factor in the numberator rather than the denominator to avoid
> + * integer overflow
s/numberator/numerator/
With that, this patch is:
Reviewed-by: Lyude Paul <lyude@xxxxxxxxxx>
> */
>
> numerator = 64 * 1006;
> denominator = 54 * 8 * 1000 * 1000;
>
> + if (dsc)
> + numerator /= 16;
> +
> kbps *= numerator;
> peak_kbps = drm_fixp_from_fraction(kbps, denominator);
>
> @@ -3570,19 +3578,19 @@ EXPORT_SYMBOL(drm_dp_calc_pbn_mode);
> static int test_calc_pbn_mode(void)
> {
> int ret;
> - ret = drm_dp_calc_pbn_mode(154000, 30);
> + ret = drm_dp_calc_pbn_mode(154000, 30, false);
> if (ret != 689) {
> DRM_ERROR("PBN calculation test failed - clock %d, bpp %d,
> expected PBN %d, actual PBN %d.\n",
> 154000, 30, 689, ret);
> return -EINVAL;
> }
> - ret = drm_dp_calc_pbn_mode(234000, 30);
> + ret = drm_dp_calc_pbn_mode(234000, 30, false);
> if (ret != 1047) {
> DRM_ERROR("PBN calculation test failed - clock %d, bpp %d,
> expected PBN %d, actual PBN %d.\n",
> 234000, 30, 1047, ret);
> return -EINVAL;
> }
> - ret = drm_dp_calc_pbn_mode(297000, 24);
> + ret = drm_dp_calc_pbn_mode(297000, 24, false);
> if (ret != 1063) {
> DRM_ERROR("PBN calculation test failed - clock %d, bpp %d,
> expected PBN %d, actual PBN %d.\n",
> 297000, 24, 1063, ret);
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> index 2c5ac3dd647f..4f17f61f4453 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> @@ -61,7 +61,7 @@ static int intel_dp_mst_compute_link_config(struct
> intel_encoder *encoder,
> crtc_state->pipe_bpp = bpp;
>
> crtc_state->pbn = drm_dp_calc_pbn_mode(adjusted_mode-
> >crtc_clock,
> - crtc_state->pipe_bpp);
> + crtc_state->pipe_bpp,
> false);
>
> slots = drm_dp_atomic_find_vcpi_slots(state, &intel_dp-
> >mst_mgr,
> port, crtc_state->pbn);
> diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c
> b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> index 5c36c75232e6..c68783c1f3fa 100644
> --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
> +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> @@ -782,7 +782,7 @@ nv50_msto_atomic_check(struct drm_encoder *encoder,
> const int bpp = connector->display_info.bpc * 3;
> const int clock = crtc_state->adjusted_mode.clock;
>
> - asyh->dp.pbn = drm_dp_calc_pbn_mode(clock, bpp);
> + asyh->dp.pbn = drm_dp_calc_pbn_mode(clock, bpp,
> false);
> }
>
> slots = drm_dp_atomic_find_vcpi_slots(state, &mstm->mgr,
> diff --git a/drivers/gpu/drm/radeon/radeon_dp_mst.c
> b/drivers/gpu/drm/radeon/radeon_dp_mst.c
> index 2994f07fbad9..c997f88218f2 100644
> --- a/drivers/gpu/drm/radeon/radeon_dp_mst.c
> +++ b/drivers/gpu/drm/radeon/radeon_dp_mst.c
> @@ -514,7 +514,7 @@ static bool radeon_mst_mode_fixup(struct drm_encoder
> *encoder,
>
> mst_enc = radeon_encoder->enc_priv;
>
> - mst_enc->pbn = drm_dp_calc_pbn_mode(adjusted_mode->clock, bpp);
> + mst_enc->pbn = drm_dp_calc_pbn_mode(adjusted_mode->clock, bpp, false);
>
> mst_enc->primary->active_device = mst_enc->primary->devices & mst_enc-
> >connector->devices;
> DRM_DEBUG_KMS("setting active device to %08x from %08x %08x for
> encoder %d\n",
> diff --git a/include/drm/drm_dp_mst_helper.h
> b/include/drm/drm_dp_mst_helper.h
> index 2ba6253ea6d3..9116b2c95239 100644
> --- a/include/drm/drm_dp_mst_helper.h
> +++ b/include/drm/drm_dp_mst_helper.h
> @@ -610,8 +610,7 @@ bool drm_dp_mst_port_has_audio(struct
> drm_dp_mst_topology_mgr *mgr,
> 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_calc_pbn_mode(int clock, int bpp);
> -
> +int drm_dp_calc_pbn_mode(int clock, int bpp, bool dsc);
>
> bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
> struct drm_dp_mst_port *port, int pbn, int
> slots);
--
Cheers,
Lyude Paul
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