On Thu, Sep 14, 2023 at 10:26:44PM +0300, Imre Deak wrote:
> At the moment modesetting pipe C on IVB will fail if pipe B uses 4 FDI
> lanes. Make the BW sharing more dynamic by trying to reduce pipe B's
> link bpp in this case, until pipe B uses only up to 2 FDI lanes.
>
> For this instead of the encoder compute config retry loop - which
> reduced link bpp only for the encoder's pipe - reduce the maximum link
> bpp for pipe B/C as required after all CRTC states are computed and
> recompute the CRTC states with the new bpp limit.
>
> v2:
> - Don't assume that a CRTC is already in the atomic state, while
> reducing its link bpp.
> - Add DocBook description to intel_fdi_atomic_check_link().
> v3:
> - Enable BW management for FDI links in a separate patch. (Ville)
>
> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/g4x_hdmi.c | 6 +-
> drivers/gpu/drm/i915/display/intel_crt.c | 7 ++
> drivers/gpu/drm/i915/display/intel_display.c | 14 +---
> drivers/gpu/drm/i915/display/intel_dp.c | 3 +-
> drivers/gpu/drm/i915/display/intel_fdi.c | 87 +++++++++++++++-----
> drivers/gpu/drm/i915/display/intel_fdi.h | 4 +
> drivers/gpu/drm/i915/display/intel_link_bw.c | 7 +-
> drivers/gpu/drm/i915/display/intel_lvds.c | 10 ++-
> drivers/gpu/drm/i915/display/intel_sdvo.c | 10 ++-
> 9 files changed, 107 insertions(+), 41 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/g4x_hdmi.c b/drivers/gpu/drm/i915/display/g4x_hdmi.c
> index 634b14116d9dd..8b5d26cd3b85e 100644
> --- a/drivers/gpu/drm/i915/display/g4x_hdmi.c
> +++ b/drivers/gpu/drm/i915/display/g4x_hdmi.c
> @@ -19,6 +19,7 @@
> #include "intel_fifo_underrun.h"
> #include "intel_hdmi.h"
> #include "intel_hotplug.h"
> +#include "intel_link_bw.h"
> #include "intel_sdvo.h"
> #include "vlv_sideband.h"
>
> @@ -133,8 +134,11 @@ static int g4x_hdmi_compute_config(struct intel_encoder *encoder,
> struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
> struct drm_i915_private *i915 = to_i915(encoder->base.dev);
>
> - if (HAS_PCH_SPLIT(i915))
> + if (HAS_PCH_SPLIT(i915)) {
> crtc_state->has_pch_encoder = true;
> + if (!intel_link_bw_compute_pipe_bpp(crtc_state))
> + return -EINVAL;
> + }
>
> if (IS_G4X(i915))
> crtc_state->has_hdmi_sink = g4x_compute_has_hdmi_sink(state, crtc);
> diff --git a/drivers/gpu/drm/i915/display/intel_crt.c b/drivers/gpu/drm/i915/display/intel_crt.c
> index f6df6c4fa72ef..7aa89d0fa3d6c 100644
> --- a/drivers/gpu/drm/i915/display/intel_crt.c
> +++ b/drivers/gpu/drm/i915/display/intel_crt.c
> @@ -49,6 +49,7 @@
> #include "intel_gmbus.h"
> #include "intel_hotplug.h"
> #include "intel_hotplug_irq.h"
> +#include "intel_link_bw.h"
> #include "intel_load_detect.h"
> #include "intel_pch_display.h"
> #include "intel_pch_refclk.h"
> @@ -413,6 +414,9 @@ static int pch_crt_compute_config(struct intel_encoder *encoder,
> return -EINVAL;
>
> pipe_config->has_pch_encoder = true;
> + if (!intel_link_bw_compute_pipe_bpp(pipe_config))
> + return -EINVAL;
> +
> pipe_config->output_format = INTEL_OUTPUT_FORMAT_RGB;
>
> return 0;
> @@ -435,6 +439,9 @@ static int hsw_crt_compute_config(struct intel_encoder *encoder,
> return -EINVAL;
>
> pipe_config->has_pch_encoder = true;
> + if (!intel_link_bw_compute_pipe_bpp(pipe_config))
> + return -EINVAL;
> +
> pipe_config->output_format = INTEL_OUTPUT_FORMAT_RGB;
>
> /* LPT FDI RX only supports 8bpc. */
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index 29816153fdd59..aad16dcceb788 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -4607,7 +4607,6 @@ intel_modeset_pipe_config(struct intel_atomic_state *state,
> struct drm_connector_state *connector_state;
> int pipe_src_w, pipe_src_h;
> int base_bpp, ret, i;
> - bool retry = true;
>
> crtc_state->cpu_transcoder = (enum transcoder) crtc->pipe;
>
> @@ -4637,6 +4636,7 @@ intel_modeset_pipe_config(struct intel_atomic_state *state,
> "[CRTC:%d:%s] Link bpp limited to " BPP_X16_FMT "\n",
> crtc->base.base.id, crtc->base.name,
> BPP_X16_ARGS(crtc_state->max_link_bpp_x16));
> + crtc_state->bw_constrained = true;
> }
>
> base_bpp = crtc_state->pipe_bpp;
> @@ -4680,7 +4680,6 @@ intel_modeset_pipe_config(struct intel_atomic_state *state,
> crtc_state->output_types |= BIT(encoder->type);
> }
>
> -encoder_retry:
> /* Ensure the port clock defaults are reset when retrying. */
> crtc_state->port_clock = 0;
> crtc_state->pixel_multiplier = 1;
> @@ -4720,17 +4719,6 @@ intel_modeset_pipe_config(struct intel_atomic_state *state,
> ret = intel_crtc_compute_config(state, crtc);
> if (ret == -EDEADLK)
> return ret;
> - if (ret == -EAGAIN) {
> - if (drm_WARN(&i915->drm, !retry,
> - "[CRTC:%d:%s] loop in pipe configuration computation\n",
> - crtc->base.base.id, crtc->base.name))
> - return -EINVAL;
> -
> - drm_dbg_kms(&i915->drm, "[CRTC:%d:%s] bw constrained, retrying\n",
> - crtc->base.base.id, crtc->base.name);
> - retry = false;
> - goto encoder_retry;
> - }
> if (ret < 0) {
> drm_dbg_kms(&i915->drm, "[CRTC:%d:%s] config failure: %d\n",
> crtc->base.base.id, crtc->base.name, ret);
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index d5e6813d36c8f..03010accc1c7f 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -2219,7 +2219,8 @@ intel_dp_compute_config_link_bpp_limits(struct intel_dp *intel_dp,
> const struct intel_encoder *encoder = &dp_to_dig_port(intel_dp)->base;
> int max_link_bpp_x16;
>
> - max_link_bpp_x16 = to_bpp_x16(limits->pipe.max_bpp);
> + max_link_bpp_x16 = min(crtc_state->max_link_bpp_x16,
> + to_bpp_x16(limits->pipe.max_bpp));
>
> if (!dsc) {
> max_link_bpp_x16 = rounddown(max_link_bpp_x16, to_bpp_x16(2 * 3));
> diff --git a/drivers/gpu/drm/i915/display/intel_fdi.c b/drivers/gpu/drm/i915/display/intel_fdi.c
> index 4d7d524c68017..ad01915a4a39b 100644
> --- a/drivers/gpu/drm/i915/display/intel_fdi.c
> +++ b/drivers/gpu/drm/i915/display/intel_fdi.c
> @@ -13,6 +13,7 @@
> #include "intel_display_types.h"
> #include "intel_fdi.h"
> #include "intel_fdi_regs.h"
> +#include "intel_link_bw.h"
>
> struct intel_fdi_funcs {
> void (*fdi_link_train)(struct intel_crtc *crtc,
> @@ -129,13 +130,16 @@ static int pipe_required_fdi_lanes(struct intel_crtc_state *crtc_state)
> }
>
> static int ilk_check_fdi_lanes(struct drm_device *dev, enum pipe pipe,
> - struct intel_crtc_state *pipe_config)
> + struct intel_crtc_state *pipe_config,
> + enum pipe *pipe_to_reduce)
> {
> struct drm_i915_private *dev_priv = to_i915(dev);
> struct drm_atomic_state *state = pipe_config->uapi.state;
> struct intel_crtc *other_crtc;
> struct intel_crtc_state *other_crtc_state;
>
> + *pipe_to_reduce = pipe;
> +
> drm_dbg_kms(&dev_priv->drm,
> "checking fdi config on pipe %c, lanes %i\n",
> pipe_name(pipe), pipe_config->fdi_lanes);
> @@ -198,6 +202,9 @@ static int ilk_check_fdi_lanes(struct drm_device *dev, enum pipe pipe,
> if (pipe_required_fdi_lanes(other_crtc_state) > 2) {
> drm_dbg_kms(&dev_priv->drm,
> "fdi link B uses too many lanes to enable link C\n");
> +
> + *pipe_to_reduce = PIPE_B;
> +
> return -EINVAL;
> }
> return 0;
> @@ -238,10 +245,8 @@ int ilk_fdi_compute_config(struct intel_crtc *crtc,
> struct drm_device *dev = crtc->base.dev;
> struct drm_i915_private *i915 = to_i915(dev);
> const struct drm_display_mode *adjusted_mode = &pipe_config->hw.adjusted_mode;
> - int lane, link_bw, fdi_dotclock, ret;
> - bool needs_recompute = false;
> + int lane, link_bw, fdi_dotclock;
>
> -retry:
> /* FDI is a binary signal running at ~2.7GHz, encoding
> * each output octet as 10 bits. The actual frequency
> * is stored as a divider into a 100MHz clock, and the
> @@ -261,25 +266,69 @@ int ilk_fdi_compute_config(struct intel_crtc *crtc,
> intel_link_compute_m_n(pipe_config->pipe_bpp, lane, fdi_dotclock,
> link_bw, &pipe_config->fdi_m_n, false);
>
> - ret = ilk_check_fdi_lanes(dev, crtc->pipe, pipe_config);
> - if (ret == -EDEADLK)
> + return 0;
> +}
> +
> +static int intel_fdi_atomic_check_bw(struct intel_atomic_state *state,
> + struct intel_crtc *crtc,
> + struct intel_crtc_state *pipe_config,
> + struct intel_link_bw_limits *limits)
> +{
> + struct drm_i915_private *i915 = to_i915(crtc->base.dev);
> + enum pipe pipe_to_reduce;
> + int ret;
> +
> + ret = ilk_check_fdi_lanes(&i915->drm, crtc->pipe, pipe_config,
> + &pipe_to_reduce);
> + if (ret != -EINVAL)
> return ret;
>
> - if (ret == -EINVAL && pipe_config->pipe_bpp > 6*3) {
> - pipe_config->pipe_bpp -= 2*3;
> - drm_dbg_kms(&i915->drm,
> - "fdi link bw constraint, reducing pipe bpp to %i\n",
> - pipe_config->pipe_bpp);
> - needs_recompute = true;
> - pipe_config->bw_constrained = true;
> -
> - goto retry;
> + ret = intel_link_bw_reduce_bpp(state, limits,
> + BIT(pipe_to_reduce),
> + "FDI link BW");
> +
> + return ret ? : -EAGAIN;
> +}
> +
> +/**
> + * intel_fdi_atomic_check_link - check all modeset FDI link configuration
> + * @state: intel atomic state
> + * @limits: link BW limits
> + *
> + * Check the link configuration for all modeset FDI outputs. If the
> + * configuration is invalid @limits will be updated if possible to
> + * reduce the total BW, after which the configuration for all CRTCs in
> + * @state must be recomputed with the updated @limits.
> + *
> + * Returns:
> + * - 0 if the confugration is valid
> + * - %-EAGAIN, if the configuration is invalid and @limits got updated
> + * with fallback values with which the configuration of all CRTCs
> + * in @state must be recomputed
> + * - Other negative error, if the configuration is invalid without a
> + * fallback possibility, or the check failed for another reason
> + */
> +int intel_fdi_atomic_check_link(struct intel_atomic_state *state,
> + struct intel_link_bw_limits *limits)
> +{
> + struct intel_crtc *crtc;
> + struct intel_crtc_state *crtc_state;
> + int i;
> +
> + for_each_new_intel_crtc_in_state(state, crtc, crtc_state, i) {
> + int ret;
> +
> + if (!crtc_state->has_pch_encoder ||
> + !intel_crtc_needs_modeset(crtc_state) ||
> + !crtc_state->hw.enable)
> + continue;
> +
> + ret = intel_fdi_atomic_check_bw(state, crtc, crtc_state, limits);
> + if (ret)
> + return ret;
> }
>
> - if (needs_recompute)
> - return -EAGAIN;
> -
> - return ret;
> + return 0;
> }
>
> static void cpt_set_fdi_bc_bifurcation(struct drm_i915_private *dev_priv, bool enable)
> diff --git a/drivers/gpu/drm/i915/display/intel_fdi.h b/drivers/gpu/drm/i915/display/intel_fdi.h
> index 1cdb86172702f..129444c580f27 100644
> --- a/drivers/gpu/drm/i915/display/intel_fdi.h
> +++ b/drivers/gpu/drm/i915/display/intel_fdi.h
> @@ -8,14 +8,18 @@
>
> enum pipe;
> struct drm_i915_private;
> +struct intel_atomic_state;
> struct intel_crtc;
> struct intel_crtc_state;
> struct intel_encoder;
> +struct intel_link_bw_limits;
>
> 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,
> struct intel_crtc_state *pipe_config);
> +int intel_fdi_atomic_check_link(struct intel_atomic_state *state,
> + struct intel_link_bw_limits *limits);
> void intel_fdi_normal_train(struct intel_crtc *crtc);
> void ilk_fdi_disable(struct intel_crtc *crtc);
> void ilk_fdi_pll_disable(struct intel_crtc *intel_crtc);
> diff --git a/drivers/gpu/drm/i915/display/intel_link_bw.c b/drivers/gpu/drm/i915/display/intel_link_bw.c
> index 22494772b9d59..aacf22bab3135 100644
> --- a/drivers/gpu/drm/i915/display/intel_link_bw.c
> +++ b/drivers/gpu/drm/i915/display/intel_link_bw.c
> @@ -160,7 +160,12 @@ intel_link_bw_reset_pipe_limit_to_min(struct intel_atomic_state *state,
> static int check_all_link_config(struct intel_atomic_state *state,
> struct intel_link_bw_limits *limits)
> {
> - /* TODO: Check all shared display link configurations like FDI */
> + int ret;
> +
> + ret = intel_fdi_atomic_check_link(state, limits);
> + if (ret)
> + return ret;
> +
> return 0;
> }
>
> diff --git a/drivers/gpu/drm/i915/display/intel_lvds.c b/drivers/gpu/drm/i915/display/intel_lvds.c
> index 3ace56979b70e..0366d4cc6b72b 100644
> --- a/drivers/gpu/drm/i915/display/intel_lvds.c
> +++ b/drivers/gpu/drm/i915/display/intel_lvds.c
> @@ -48,6 +48,7 @@
> #include "intel_dpll.h"
> #include "intel_fdi.h"
> #include "intel_gmbus.h"
> +#include "intel_link_bw.h"
> #include "intel_lvds.h"
> #include "intel_lvds_regs.h"
> #include "intel_panel.h"
> @@ -425,6 +426,12 @@ static int intel_lvds_compute_config(struct intel_encoder *encoder,
> return -EINVAL;
> }
>
> + if (HAS_PCH_SPLIT(i915)) {
> + crtc_state->has_pch_encoder = true;
> + if (!intel_link_bw_compute_pipe_bpp(crtc_state))
> + return -EINVAL;
> + }
> +
> if (lvds_encoder->a3_power == LVDS_A3_POWER_UP)
> lvds_bpp = 8*3;
> else
> @@ -453,9 +460,6 @@ static int intel_lvds_compute_config(struct intel_encoder *encoder,
> if (adjusted_mode->flags & DRM_MODE_FLAG_DBLSCAN)
> return -EINVAL;
>
> - if (HAS_PCH_SPLIT(i915))
> - crtc_state->has_pch_encoder = true;
> -
> ret = intel_panel_fitting(crtc_state, conn_state);
> if (ret)
> return ret;
> diff --git a/drivers/gpu/drm/i915/display/intel_sdvo.c b/drivers/gpu/drm/i915/display/intel_sdvo.c
> index 135a2527fd1b4..3c912f3bc10ba 100644
> --- a/drivers/gpu/drm/i915/display/intel_sdvo.c
> +++ b/drivers/gpu/drm/i915/display/intel_sdvo.c
> @@ -48,6 +48,7 @@
> #include "intel_gmbus.h"
> #include "intel_hdmi.h"
> #include "intel_hotplug.h"
> +#include "intel_link_bw.h"
> #include "intel_panel.h"
> #include "intel_sdvo.h"
> #include "intel_sdvo_regs.h"
> @@ -1351,14 +1352,17 @@ static int intel_sdvo_compute_config(struct intel_encoder *encoder,
> struct drm_display_mode *adjusted_mode = &pipe_config->hw.adjusted_mode;
> struct drm_display_mode *mode = &pipe_config->hw.mode;
>
> + if (HAS_PCH_SPLIT(to_i915(encoder->base.dev))) {
> + pipe_config->has_pch_encoder = true;
> + if (!intel_link_bw_compute_pipe_bpp(pipe_config))
> + return -EINVAL;
> + }
> +
> DRM_DEBUG_KMS("forcing bpc to 8 for SDVO\n");
> pipe_config->pipe_bpp = 8*3;
This seems borked. I think we want to force this to 8bpc only if we're
higher currently. Same for the LVDS case I think, though that one is a
bit more sane atm since it looks at the bw_constrained flag, though
I don't think we really need that flag anymore, at least for this
purpose. Hmm, but maybe we do still need it for the LPT FDI case
where we do actually want to increase the bpc to 8 if the EDID
baseline is below that.
> pipe_config->sink_format = INTEL_OUTPUT_FORMAT_RGB;
> pipe_config->output_format = INTEL_OUTPUT_FORMAT_RGB;
>
> - if (HAS_PCH_SPLIT(to_i915(encoder->base.dev)))
> - pipe_config->has_pch_encoder = true;
> -
> /*
> * We need to construct preferred input timings based on our
> * output timings. To do that, we have to set the output
> --
> 2.37.2
--
Ville Syrjälä
Intel
