On Mon, Sep 11, 2023 at 09:59:34PM +0300, Ville Syrjälä wrote:
> On Thu, Aug 24, 2023 at 11:05:03AM +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 - check the overall BW
> > limits after all CRTC states have been computed and if the check fails
> > reduce the maximum link bpp for a selected pipe (for FDI pipe B or C as
> > required) and recompute all the CRTC states. Retry this sequence until
> > either the overall BW limit check passes, or further bpp reduction is
> > not possible (because all pipes/encoders sharing the link BW reached
> > their minimum link bpp).
> >
> > This change also prepares for an upcoming patch resolving BW limits in
> > a similar way on MST links as well.
> >
> > v2:
> > - Rename intel_crtc_state::max_link_bpp to max_link_bpp_x16 and
> > intel_link_bw_limits::max_bpp to max_bpp_x16. (Jani)
> > - Increase back pipe B's link bpp if earlier it was limited due to
> > pipe C and pipe C gets later disabled.
> > - 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().
> >
> > Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
> > Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx>
> > ---
> > drivers/gpu/drm/i915/display/g4x_hdmi.c | 5 +-
> > drivers/gpu/drm/i915/display/intel_atomic.c | 207 ++++++++++++++++++
> > drivers/gpu/drm/i915/display/intel_atomic.h | 8 +
> > drivers/gpu/drm/i915/display/intel_crt.c | 7 +
> > drivers/gpu/drm/i915/display/intel_crtc.c | 1 +
> > drivers/gpu/drm/i915/display/intel_display.c | 44 ++--
> > drivers/gpu/drm/i915/display/intel_display.h | 4 +
> > .../drm/i915/display/intel_display_types.h | 9 +-
> > drivers/gpu/drm/i915/display/intel_dp.c | 3 +-
> > drivers/gpu/drm/i915/display/intel_fdi.c | 137 ++++++++++--
> > drivers/gpu/drm/i915/display/intel_fdi.h | 5 +
> > drivers/gpu/drm/i915/display/intel_lvds.c | 9 +-
> > drivers/gpu/drm/i915/display/intel_sdvo.c | 9 +-
> > 13 files changed, 404 insertions(+), 44 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/g4x_hdmi.c b/drivers/gpu/drm/i915/display/g4x_hdmi.c
> > index 634b14116d9dd..ebbceddc13259 100644
> > --- a/drivers/gpu/drm/i915/display/g4x_hdmi.c
> > +++ b/drivers/gpu/drm/i915/display/g4x_hdmi.c
> > @@ -133,8 +133,11 @@ 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_atomic_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_atomic.c b/drivers/gpu/drm/i915/display/intel_atomic.c
> > index 7cf51dd8c0567..ee4cbf80ddb55 100644
> > --- a/drivers/gpu/drm/i915/display/intel_atomic.c
> > +++ b/drivers/gpu/drm/i915/display/intel_atomic.c
>
> Not convinced we should put anything there. I think I mostly managed to
> move a bunch or semi-random stuff out now, so all it more or less has is
> the struct intel_atomic_state alloc/free stuff.
>
> You have intel_atomic_check() in intel_display.c and the lower level
> intel_atomic_check_config() is also there, but now the middle man
> intel_atomic_check_config_and_link() ended up in intel_atomic.c for
> whatever reason. I'd just shove all of it into intel_display.c.
I didn't want to add more stuff to intel_display.c, but yes
intel_atomic.c is not the best place for these. How about moving the
link BW config/check functions instead to intel_link_bw.c as in
https://github.com/ideak/linux/commit/9fd9d456da53 ?
> The patch is also rather massive.
I thought it's easier to understand if new function definitions / their
use is in one patch, but I guess here the amount of changes vs. just
additions makes it less clear.
> Can we try to chunk it up to eg. something like:
> 1) add the new infrastructure
> 2) convert the fdi retry stuff to use the new infrastructure
> 3) add intel_fdi_add_affected_crtcs() (which seems more or less
> independent from the rest of the fdi conversion?)
Yes, 3) can be regarded as an additional functionality.
> ?
Ok, will split the changes based on the above points.
> > @@ -38,6 +38,7 @@
> > #include "intel_atomic.h"
> > #include "intel_cdclk.h"
> > #include "intel_display_types.h"
> > +#include "intel_fdi.h"
> > #include "intel_global_state.h"
> > #include "intel_hdcp.h"
> > #include "intel_psr.h"
> > @@ -358,3 +359,209 @@ intel_atomic_get_crtc_state(struct drm_atomic_state *state,
> >
> > return to_intel_crtc_state(crtc_state);
> > }
> > +
> > +/**
> > + * intel_atomic_compute_pipe_bpp - compute pipe bpp limited by max link bpp
> > + * @crtc_state: the crtc state
> > + *
> > + * Compute the pipe bpp limited by the CRTC's maximum link bpp. Encoders can
> > + * call this function during state computation in the simple case where the
> > + * link bpp will always match the pipe bpp. This is the case for all non-DP
> > + * encoders, while DP encoders will use a link bpp lower than pipe bpp in case
> > + * of DSC compression.
> > + *
> > + * Returns %true in case of success, %false if pipe bpp would need to be
> > + * reduced below its valid range.
> > + */
> > +bool intel_atomic_compute_pipe_bpp(struct intel_crtc_state *crtc_state)
> > +{
> > + int pipe_bpp = min(crtc_state->pipe_bpp,
> > + to_bpp_int(crtc_state->max_link_bpp_x16));
> > +
> > + pipe_bpp = rounddown(pipe_bpp, 2 * 3);
> > +
> > + if (pipe_bpp < 6 * 3)
> > + return false;
> > +
> > + crtc_state->pipe_bpp = pipe_bpp;
> > +
> > + return true;
> > +}
> > +
> > +/**
> > + * intel_atomic_reduce_link_bpp - reduce maximum link bpp for a selected pipe
> > + * @state: atomic state
> > + * @limits: link BW limits
> > + * @pipe_mask: mask of pipes to select from
> > + * @reason: explanation of why bpp reduction is needed
> > + *
> > + * Select the pipe from @pipe_mask with the biggest link bpp value and set the
> > + * maximum of link bpp in @limits below this value. Modeset the selected pipe,
> > + * so that its state will get recomputed.
> > + *
> > + * This function can be called to resolve a link's BW overallocation by reducing
> > + * the link bpp of one pipe on the link and hence reducing the total link BW.
> > + *
> > + * Returns
> > + * - 0 in case of success
> > + * - %-EINVAL if no pipe can further reduce its link bpp
> > + * - Other negative error, if modesetting the selected pipe failed
> > + */
> > +int intel_atomic_reduce_link_bpp(struct intel_atomic_state *state,
> > + struct intel_link_bw_limits *limits,
> > + u8 pipe_mask,
> > + const char *reason)
> > +{
> > + struct drm_i915_private *i915 = to_i915(state->base.dev);
> > + enum pipe max_bpp_pipe = INVALID_PIPE;
> > + struct intel_crtc *crtc;
> > + int max_bpp = 0;
> > +
> > + for_each_intel_crtc_in_pipe_mask(&i915->drm, crtc, pipe_mask) {
> > + struct intel_crtc_state *crtc_state;
> > + int pipe_bpp;
> > +
> > + if (limits->min_bpp_pipes & BIT(crtc->pipe))
> > + continue;
> > +
> > + crtc_state = intel_atomic_get_crtc_state(&state->base,
> > + crtc);
> > + if (IS_ERR(crtc_state))
> > + return PTR_ERR(crtc_state);
> > +
> > + if (crtc_state->dsc.compression_enable)
> > + pipe_bpp = crtc_state->dsc.compressed_bpp;
> > + else
> > + pipe_bpp = crtc_state->pipe_bpp;
> > +
> > + if (pipe_bpp > max_bpp) {
> > + max_bpp = pipe_bpp;
> > + max_bpp_pipe = crtc->pipe;
> > + }
> > + }
> > +
> > + if (max_bpp_pipe == INVALID_PIPE)
> > + return -EINVAL;
> > +
> > + limits->max_bpp_x16[max_bpp_pipe] = to_bpp_x16(max_bpp) - 1;
> > +
> > + return intel_modeset_pipes_in_mask(state, reason,
> > + BIT(max_bpp_pipe), false);
> > +}
> > +
> > +static int intel_atomic_check_link(struct intel_atomic_state *state,
> > + struct intel_link_bw_limits *limits)
> > +{
> > + int ret;
> > +
> > + ret = intel_fdi_atomic_check_link(state, limits);
> > + if (ret)
> > + return ret;
> > +
> > + return 0;
> > +}
> > +
> > +static bool
> > +assert_link_limit_change_valid(struct drm_i915_private *i915,
> > + const struct intel_link_bw_limits *old_limits,
> > + const struct intel_link_bw_limits *new_limits)
> > +{
> > + bool bpps_changed = false;
> > + enum pipe pipe;
> > +
> > + for_each_pipe(i915, pipe) {
> > + /* The bpp limit can only decrease. */
> > + if (drm_WARN_ON(&i915->drm,
> > + new_limits->max_bpp_x16[pipe] >
> > + old_limits->max_bpp_x16[pipe]))
> > + return false;
> > +
> > + if (new_limits->max_bpp_x16[pipe] <
> > + old_limits->max_bpp_x16[pipe])
> > + bpps_changed = true;
> > + }
> > +
> > + if (drm_WARN_ON(&i915->drm,
> > + !bpps_changed))
> > + return false;
> > +
> > + return true;
> > +}
> > +
> > +static bool
> > +reset_link_bpp_limit_to_min(struct intel_atomic_state *state,
> > + const struct intel_link_bw_limits *old_limits,
> > + struct intel_link_bw_limits *new_limits,
> > + enum pipe failed_pipe)
> > +{
> > + if (failed_pipe == INVALID_PIPE)
> > + return false;
> > +
> > + if (new_limits->min_bpp_pipes & BIT(failed_pipe))
> > + return false;
> > +
> > + if (new_limits->max_bpp_x16[failed_pipe] ==
> > + old_limits->max_bpp_x16[failed_pipe])
> > + return false;
> > +
> > + new_limits->max_bpp_x16[failed_pipe] =
> > + old_limits->max_bpp_x16[failed_pipe];
> > + new_limits->min_bpp_pipes |= BIT(failed_pipe);
> > +
> > + return true;
> > +}
> > +
> > +/**
> > + * intel_atomic_check_config_and_link - compute CRTC configs, resolving any BW limits
> > + * @state: atomic state
> > + *
> > + * Compute the configuration of all CRTCs in @state and resolve any BW
> > + * limitations on links shared by these CRTCs.
> > + *
> > + * Return 0 in case of success, or a negative error code otherwise.
> > + */
> > +int intel_atomic_check_config_and_link(struct intel_atomic_state *state)
> > +{
> > + struct drm_i915_private *i915 = to_i915(state->base.dev);
> > + struct intel_link_bw_limits new_limits = {};
> > + struct intel_link_bw_limits old_limits;
> > + enum pipe pipe;
> > + int ret;
> > +
> > + for_each_pipe(i915, pipe)
> > + new_limits.max_bpp_x16[pipe] = INT_MAX;
> > +
> > + old_limits = new_limits;
> > +
> > + while (true) {
> > + enum pipe failed_pipe;
> > +
> > + ret = intel_atomic_check_config(state, &new_limits,
> > + &failed_pipe);
> > + if (ret) {
> > + if (ret == -EINVAL &&
> > + reset_link_bpp_limit_to_min(state,
> > + &old_limits,
> > + &new_limits,
> > + failed_pipe))
> > + continue;
> > +
> > + break;
> > + }
> > +
> > + old_limits = new_limits;
> > +
> > + ret = intel_atomic_check_link(state, &new_limits);
> > + if (ret != -EAGAIN)
> > + break;
> > +
> > + if (!assert_link_limit_change_valid(i915,
> > + &old_limits,
> > + &new_limits)) {
> > + ret = -EINVAL;
> > + break;
> > + }
> > + }
> > +
> > + return ret;
> > +}
> > diff --git a/drivers/gpu/drm/i915/display/intel_atomic.h b/drivers/gpu/drm/i915/display/intel_atomic.h
> > index e506f6a873447..bbf3595d52c41 100644
> > --- a/drivers/gpu/drm/i915/display/intel_atomic.h
> > +++ b/drivers/gpu/drm/i915/display/intel_atomic.h
> > @@ -20,6 +20,7 @@ struct intel_atomic_state;
> > struct intel_connector;
> > struct intel_crtc;
> > struct intel_crtc_state;
> > +struct intel_link_bw_limits;
> >
> > int intel_digital_connector_atomic_get_property(struct drm_connector *connector,
> > const struct drm_connector_state *state,
> > @@ -52,4 +53,11 @@ struct intel_crtc_state *
> > intel_atomic_get_crtc_state(struct drm_atomic_state *state,
> > struct intel_crtc *crtc);
> >
> > +int intel_atomic_reduce_link_bpp(struct intel_atomic_state *state,
> > + struct intel_link_bw_limits *limits,
> > + u8 pipe_mask,
> > + const char *reason);
> > +bool intel_atomic_compute_pipe_bpp(struct intel_crtc_state *crtc_state);
> > +int intel_atomic_check_config_and_link(struct intel_atomic_state *state);
> > +
> > #endif /* __INTEL_ATOMIC_H__ */
> > diff --git a/drivers/gpu/drm/i915/display/intel_crt.c b/drivers/gpu/drm/i915/display/intel_crt.c
> > index f66340b4caf0f..3322080a574e8 100644
> > --- a/drivers/gpu/drm/i915/display/intel_crt.c
> > +++ b/drivers/gpu/drm/i915/display/intel_crt.c
> > @@ -36,6 +36,7 @@
> > #include "i915_drv.h"
> > #include "i915_irq.h"
> > #include "i915_reg.h"
> > +#include "intel_atomic.h"
> > #include "intel_connector.h"
> > #include "intel_crt.h"
> > #include "intel_crtc.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_atomic_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_atomic_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_crtc.c b/drivers/gpu/drm/i915/display/intel_crtc.c
> > index 182c6dd64f47c..1eda6a9f19aa8 100644
> > --- a/drivers/gpu/drm/i915/display/intel_crtc.c
> > +++ b/drivers/gpu/drm/i915/display/intel_crtc.c
> > @@ -175,6 +175,7 @@ void intel_crtc_state_reset(struct intel_crtc_state *crtc_state,
> > crtc_state->hsw_workaround_pipe = INVALID_PIPE;
> > crtc_state->scaler_state.scaler_id = -1;
> > crtc_state->mst_master_transcoder = INVALID_TRANSCODER;
> > + crtc_state->max_link_bpp_x16 = INT_MAX;
> > }
> >
> > static struct intel_crtc *intel_crtc_alloc(void)
> > diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> > index dbf109a2e738f..32778bd01bb05 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display.c
> > +++ b/drivers/gpu/drm/i915/display/intel_display.c
> > @@ -4641,7 +4641,8 @@ intel_crtc_prepare_cleared_state(struct intel_atomic_state *state,
> >
> > static int
> > intel_modeset_pipe_config(struct intel_atomic_state *state,
> > - struct intel_crtc *crtc)
> > + struct intel_crtc *crtc,
> > + const struct intel_link_bw_limits *limits)
> > {
> > struct drm_i915_private *i915 = to_i915(crtc->base.dev);
> > struct intel_crtc_state *crtc_state =
> > @@ -4650,7 +4651,6 @@ 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;
> >
> > @@ -4673,6 +4673,17 @@ intel_modeset_pipe_config(struct intel_atomic_state *state,
> > if (ret)
> > return ret;
> >
> > + crtc_state->max_link_bpp_x16 = limits->max_bpp_x16[crtc->pipe];
> > +
> > + if (crtc_state->pipe_bpp > to_bpp_int(crtc_state->max_link_bpp_x16)) {
> > + drm_dbg_kms(&i915->drm,
> > + "[CRTC:%d:%s] Link bpp limited to %d.%04d\n",
> > + crtc->base.base.id, crtc->base.name,
> > + to_bpp_int(crtc_state->max_link_bpp_x16),
> > + to_bpp_frac_dec(crtc_state->max_link_bpp_x16));
> > + crtc_state->bw_constrained = true;
> > + }
> > +
> > base_bpp = crtc_state->pipe_bpp;
> >
> > /*
> > @@ -4714,7 +4725,6 @@ 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;
> > @@ -4754,17 +4764,6 @@ 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);
> > @@ -6206,7 +6205,9 @@ static int intel_bigjoiner_add_affected_crtcs(struct intel_atomic_state *state)
> > return 0;
> > }
> >
> > -static int intel_atomic_check_config(struct intel_atomic_state *state)
> > +int intel_atomic_check_config(struct intel_atomic_state *state,
> > + struct intel_link_bw_limits *limits,
> > + enum pipe *failed_pipe)
> > {
> > struct drm_i915_private *i915 = to_i915(state->base.dev);
> > struct intel_crtc_state *new_crtc_state;
> > @@ -6214,10 +6215,16 @@ static int intel_atomic_check_config(struct intel_atomic_state *state)
> > int ret;
> > int i;
> >
> > + *failed_pipe = INVALID_PIPE;
> > +
> > ret = intel_bigjoiner_add_affected_crtcs(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))
> > @@ -6239,7 +6246,7 @@ static int intel_atomic_check_config(struct intel_atomic_state *state)
> > if (!new_crtc_state->hw.enable)
> > continue;
> >
> > - ret = intel_modeset_pipe_config(state, crtc);
> > + ret = intel_modeset_pipe_config(state, crtc, limits);
> > if (ret)
> > break;
> >
> > @@ -6248,6 +6255,9 @@ static int intel_atomic_check_config(struct intel_atomic_state *state)
> > break;
> > }
> >
> > + if (ret)
> > + *failed_pipe = crtc->pipe;
> > +
> > return ret;
> > }
> >
> > @@ -6295,7 +6305,7 @@ int intel_atomic_check(struct drm_device *dev,
> > return ret;
> > }
> >
> > - ret = intel_atomic_check_config(state);
> > + ret = intel_atomic_check_config_and_link(state);
> > if (ret)
> > goto fail;
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_display.h b/drivers/gpu/drm/i915/display/intel_display.h
> > index d9a54610d9d5e..2e0535739bd70 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display.h
> > +++ b/drivers/gpu/drm/i915/display/intel_display.h
> > @@ -55,6 +55,7 @@ struct intel_digital_port;
> > struct intel_dp;
> > struct intel_encoder;
> > struct intel_initial_plane_config;
> > +struct intel_link_bw_limits;
> > struct intel_link_m_n;
> > struct intel_plane;
> > struct intel_plane_state;
> > @@ -391,6 +392,9 @@ enum phy_fia {
> > (new_connector_state) = to_intel_digital_connector_state((__state)->base.connectors[__i].new_state), 1))
> >
> > int intel_atomic_check(struct drm_device *dev, struct drm_atomic_state *state);
> > +int intel_atomic_check_config(struct intel_atomic_state *state,
> > + struct intel_link_bw_limits *limits,
> > + enum pipe *failed_pipe);
> > int intel_atomic_add_affected_planes(struct intel_atomic_state *state,
> > struct intel_crtc *crtc);
> > u8 intel_calc_active_pipes(struct intel_atomic_state *state,
> > diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> > index b143085b399eb..6f4f46658df22 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> > +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> > @@ -66,6 +66,12 @@ struct intel_tc_port;
> > * Display related stuff
> > */
> >
> > +struct intel_link_bw_limits {
> > + u8 min_bpp_pipes;
> > + /* in 1/16 bpp units */
> > + int max_bpp_x16[I915_MAX_PIPES];
> > +};
> > +
> > /* these are outputs from the chip - integrated only
> > external chips are via DVO or SDVO output */
> > enum intel_output_type {
> > @@ -1189,7 +1195,8 @@ struct intel_crtc_state {
> > u32 ctrl, div;
> > } dsi_pll;
> >
> > - int pipe_bpp;
> > + int max_link_bpp_x16; /* in 1/16 bpp units */
> > + int pipe_bpp; /* in 1 bpp units */
> > struct intel_link_m_n dp_m_n;
> >
> > /* m2_n2 for eDP downclock */
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> > index 6637bd4768bf7..48f005932ad8b 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> > @@ -2218,7 +2218,8 @@ 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 e12b46a84fa11..123ba67f68791 100644
> > --- a/drivers/gpu/drm/i915/display/intel_fdi.c
> > +++ b/drivers/gpu/drm/i915/display/intel_fdi.c
> > @@ -119,6 +119,59 @@ 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;
> > + struct intel_crtc *crtc;
> > +
> > + if (!IS_IVYBRIDGE(i915))
> > + 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);
> > +
> > + 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;
> > +
> > + 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(state,
> > + "FDI link BW decrease on pipe C",
> > + BIT(PIPE_B), false);
> > +}
> > +
> > /* units of 100MHz */
> > static int pipe_required_fdi_lanes(struct intel_crtc_state *crtc_state)
> > {
> > @@ -129,13 +182,16 @@ 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 +254,9 @@ 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 +297,8 @@ 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 +318,69 @@ 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;
> > + ret = intel_atomic_reduce_link_bpp(state, limits,
> > + BIT(pipe_to_reduce),
> > + "FDI link BW");
> >
> > - goto retry;
> > - }
> > + return ret ? : -EAGAIN;
> > +}
> >
> > - if (needs_recompute)
> > - return -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;
> >
> > - return 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;
> > + }
> > +
> > + 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..eb02b967bb440 100644
> > --- a/drivers/gpu/drm/i915/display/intel_fdi.h
> > +++ b/drivers/gpu/drm/i915/display/intel_fdi.h
> > @@ -8,14 +8,19 @@
> >
> > 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_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,
> > 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_lvds.c b/drivers/gpu/drm/i915/display/intel_lvds.c
> > index 3ace56979b70e..08dcc2d10a2c1 100644
> > --- a/drivers/gpu/drm/i915/display/intel_lvds.c
> > +++ b/drivers/gpu/drm/i915/display/intel_lvds.c
> > @@ -425,6 +425,12 @@ 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_atomic_compute_pipe_bpp(crtc_state))
> > + return -EINVAL;
> > + }
> > +
> > if (lvds_encoder->a3_power == LVDS_A3_POWER_UP)
> > lvds_bpp = 8*3;
> > else
> > @@ -453,9 +459,6 @@ 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 7d25a64698e2f..1c6330151f4d6 100644
> > --- a/drivers/gpu/drm/i915/display/intel_sdvo.c
> > +++ b/drivers/gpu/drm/i915/display/intel_sdvo.c
> > @@ -1352,14 +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_atomic_compute_pipe_bpp(pipe_config))
> > + return -EINVAL;
> > + }
> > +
> > DRM_DEBUG_KMS("forcing bpc to 8 for SDVO\n");
> > pipe_config->pipe_bpp = 8*3;
> > 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
