On Thu, Sep 14, 2023 at 10:26:45PM +0300, Imre Deak wrote:
> Recompute the state of all CRTCs on an FDI link during a modeset that
> may be affected by the modeset of other CRTCs on the same link. This
> ensures that each CRTC on the link maximizes its BW use (after another
> CRTC is disabled).
>
> In practice this means recomputing pipe B's config on IVB if pipe C gets
> disabled.
>
> v2:
> - Add the change recomputing affected CRTC states in a separate patch.
> (Ville)
>
> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/intel_display.c | 4 ++
> drivers/gpu/drm/i915/display/intel_fdi.c | 53 ++++++++++++++++++++
> drivers/gpu/drm/i915/display/intel_fdi.h | 1 +
> 3 files changed, 58 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index aad16dcceb788..31297a333f50e 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -6210,6 +6210,10 @@ int intel_atomic_check_config(struct intel_atomic_state *state,
> if (ret)
> return ret;
>
> + ret = intel_fdi_add_affected_crtcs(state);
> + if (ret)
> + return ret;
> +
> for_each_new_intel_crtc_in_state(state, crtc, new_crtc_state, i) {
> if (!intel_crtc_needs_modeset(new_crtc_state)) {
> if (intel_crtc_is_bigjoiner_slave(new_crtc_state))
> diff --git a/drivers/gpu/drm/i915/display/intel_fdi.c b/drivers/gpu/drm/i915/display/intel_fdi.c
> index ad01915a4a39b..d723ae7e10d71 100644
> --- a/drivers/gpu/drm/i915/display/intel_fdi.c
> +++ b/drivers/gpu/drm/i915/display/intel_fdi.c
> @@ -120,6 +120,59 @@ void intel_fdi_link_train(struct intel_crtc *crtc,
> dev_priv->display.funcs.fdi->fdi_link_train(crtc, crtc_state);
> }
>
> +/**
> + * intel_fdi_add_affected_crtcs - add CRTCs on FDI affected by other modeset CRTCs
> + * @state: intel atomic state
> + *
> + * Add a CRTC using FDI to @state if changing another CRTC's FDI BW usage is
> + * known to affect the available FDI BW for the former CRTC. In practice this
> + * means adding CRTC B on IVYBRIDGE if its use of FDI lanes is limited (by
> + * CRTC C) and CRTC C is getting disabled.
> + *
> + * Returns 0 in case of success, or a negative error code otherwise.
> + */
> +int intel_fdi_add_affected_crtcs(struct intel_atomic_state *state)
> +{
> + struct drm_i915_private *i915 = to_i915(state->base.dev);
> + struct intel_crtc_state *old_crtc_state;
> + struct intel_crtc_state *new_crtc_state;
Both look like they can be const.
> + struct intel_crtc *crtc;
> +
> + if (!IS_IVYBRIDGE(i915))
Should also check num_pipes==3 since pipe C can (at least in theory)
be fused off.
> + return 0;
> +
> + crtc = intel_crtc_for_pipe(i915, PIPE_C);
> + new_crtc_state = intel_atomic_get_new_crtc_state(state, crtc);
> +
> + if (!new_crtc_state)
> + return 0;
> +
> + old_crtc_state = intel_atomic_get_new_crtc_state(state, crtc);
old vs. new mixup
> +
> + if (!old_crtc_state->fdi_lanes)
> + return 0;
> +
> + if (!intel_crtc_needs_modeset(new_crtc_state))
> + return 0;
> +
> + if (new_crtc_state->uapi.enable)
> + return 0;
We could be switching pipe C from driving a PCH port to driving
the CPU eDP port. So this check seems a bit wrong.
> +
> + crtc = intel_crtc_for_pipe(i915, PIPE_B);
> + new_crtc_state = intel_atomic_get_crtc_state(&state->base, crtc);
> +
> + if (IS_ERR(new_crtc_state))
> + return PTR_ERR(old_crtc_state);
> +
> + old_crtc_state = intel_atomic_get_old_crtc_state(state, crtc);
> + if (!old_crtc_state->fdi_lanes)
> + return 0;
> +
> + return intel_modeset_pipes_in_mask_early(state,
> + "FDI link BW decrease on pipe C",
> + BIT(PIPE_B));
> +}
> +
> /* units of 100MHz */
> static int pipe_required_fdi_lanes(struct intel_crtc_state *crtc_state)
> {
> diff --git a/drivers/gpu/drm/i915/display/intel_fdi.h b/drivers/gpu/drm/i915/display/intel_fdi.h
> index 129444c580f27..eb02b967bb440 100644
> --- a/drivers/gpu/drm/i915/display/intel_fdi.h
> +++ b/drivers/gpu/drm/i915/display/intel_fdi.h
> @@ -14,6 +14,7 @@ struct intel_crtc_state;
> struct intel_encoder;
> struct intel_link_bw_limits;
>
> +int intel_fdi_add_affected_crtcs(struct intel_atomic_state *state);
> int intel_fdi_link_freq(struct drm_i915_private *i915,
> const struct intel_crtc_state *pipe_config);
> int ilk_fdi_compute_config(struct intel_crtc *intel_crtc,
> --
> 2.37.2
--
Ville Syrjälä
Intel
