Thanks Ville for the respin, the changes look good now.
Reviewed-by: Manasi Navare <navaremanasi@xxxxxxxxxxxx>
Manasi
On Fri, Sep 15, 2023 at 3:38 AM Ville Syrjala
<ville.syrjala@xxxxxxxxxxxxxxx> wrote:
>
> From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
>
> Implement low refresh rate (LRR) where we change the vblank
> length by hand as requested, but otherwise keep the timing
> generator running in non-VRR mode (ie. fixed refresh rate).
>
> The panel itself must support VRR for this to work, and
> only TGL+ has the double buffred TRANS_VTOTAL.VTOTAL that
> we need to make the switch properly. The double buffer
> latching happens at the start of transcoders undelayed
> vblank. The other thing that we change is
> TRANS_VBLANK.VBLANK_END but the hardware entirely ignores
> that in DP mode. But I decided to keep writing it anyway
> just to avoid more special cases in readout/state check.
>
> v2: Document that TRANS_VBLANK.VBLANK_END is ignored by
> the hardware
> v3: Reconcile with VRR fastset
> Adjust update_lrr flag behaviour
> Make sure timings stay within VRR range
> v4: Fix up update_m_n vs. update_lrr rebase fail (Manasi)
> Drop DOUBLE_BUFFER_VACTIVE define as it's not needed (Manasi)
>
> TODO: Hook LRR into the automatic DRRS downclocking stuff?
>
> Cc: Manasi Navare <navaremanasi@xxxxxxxxxxxx>
> Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/intel_atomic.c | 1 +
> drivers/gpu/drm/i915/display/intel_crtc.c | 9 +--
> drivers/gpu/drm/i915/display/intel_display.c | 60 +++++++++++++++++--
> .../drm/i915/display/intel_display_device.h | 1 +
> .../drm/i915/display/intel_display_types.h | 3 +-
> drivers/gpu/drm/i915/display/intel_vrr.c | 7 ++-
> 6 files changed, 70 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_atomic.c b/drivers/gpu/drm/i915/display/intel_atomic.c
> index aaddd8c0cfa0..5d18145da279 100644
> --- a/drivers/gpu/drm/i915/display/intel_atomic.c
> +++ b/drivers/gpu/drm/i915/display/intel_atomic.c
> @@ -260,6 +260,7 @@ intel_crtc_duplicate_state(struct drm_crtc *crtc)
>
> crtc_state->update_pipe = false;
> crtc_state->update_m_n = false;
> + crtc_state->update_lrr = false;
> crtc_state->disable_lp_wm = false;
> crtc_state->disable_cxsr = false;
> crtc_state->update_wm_pre = false;
> diff --git a/drivers/gpu/drm/i915/display/intel_crtc.c b/drivers/gpu/drm/i915/display/intel_crtc.c
> index a39e31c1ca85..22e85fe7e8aa 100644
> --- a/drivers/gpu/drm/i915/display/intel_crtc.c
> +++ b/drivers/gpu/drm/i915/display/intel_crtc.c
> @@ -495,7 +495,7 @@ static void intel_crtc_vblank_evade_scanlines(struct intel_atomic_state *state,
> if (crtc->mode_flags & I915_MODE_FLAG_VRR) {
> /* timing changes should happen with VRR disabled */
> drm_WARN_ON(state->base.dev, intel_crtc_needs_modeset(new_crtc_state) ||
> - new_crtc_state->update_m_n);
> + new_crtc_state->update_m_n || new_crtc_state->update_lrr);
>
> if (intel_vrr_is_push_sent(crtc_state))
> *vblank_start = intel_vrr_vmin_vblank_start(crtc_state);
> @@ -511,10 +511,11 @@ static void intel_crtc_vblank_evade_scanlines(struct intel_atomic_state *state,
> *max = *vblank_start - 1;
>
> /*
> - * M/N is double buffered on the transcoder's undelayed vblank,
> - * so with seamless M/N we must evade both vblanks.
> + * M/N and TRANS_VTOTAL are double buffered on the transcoder's
> + * undelayed vblank, so with seamless M/N and LRR we must evade
> + * both vblanks.
> */
> - if (new_crtc_state->update_m_n)
> + if (new_crtc_state->update_m_n || new_crtc_state->update_lrr)
> *min -= adjusted_mode->crtc_vblank_start - adjusted_mode->crtc_vdisplay;
> }
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index f0bb5c70ebfc..988558ccf794 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -928,7 +928,7 @@ static bool vrr_enabling(const struct intel_crtc_state *old_crtc_state,
> {
> return is_enabling(vrr.enable, old_crtc_state, new_crtc_state) ||
> (new_crtc_state->vrr.enable &&
> - (new_crtc_state->update_m_n ||
> + (new_crtc_state->update_m_n || new_crtc_state->update_lrr ||
> vrr_params_changed(old_crtc_state, new_crtc_state)));
> }
>
> @@ -937,7 +937,7 @@ static bool vrr_disabling(const struct intel_crtc_state *old_crtc_state,
> {
> return is_disabling(vrr.enable, old_crtc_state, new_crtc_state) ||
> (old_crtc_state->vrr.enable &&
> - (new_crtc_state->update_m_n ||
> + (new_crtc_state->update_m_n || new_crtc_state->update_lrr ||
> vrr_params_changed(old_crtc_state, new_crtc_state)));
> }
>
> @@ -2586,6 +2586,37 @@ static void intel_set_transcoder_timings(const struct intel_crtc_state *crtc_sta
> VTOTAL(crtc_vtotal - 1));
> }
>
> +static void intel_set_transcoder_timings_lrr(const struct intel_crtc_state *crtc_state)
> +{
> + struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
> + struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
> + enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
> + const struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
> + u32 crtc_vdisplay, crtc_vtotal, crtc_vblank_start, crtc_vblank_end;
> +
> + crtc_vdisplay = adjusted_mode->crtc_vdisplay;
> + crtc_vtotal = adjusted_mode->crtc_vtotal;
> + crtc_vblank_start = adjusted_mode->crtc_vblank_start;
> + crtc_vblank_end = adjusted_mode->crtc_vblank_end;
> +
> + drm_WARN_ON(&dev_priv->drm, adjusted_mode->flags & DRM_MODE_FLAG_INTERLACE);
> +
> + /*
> + * The hardware actually ignores TRANS_VBLANK.VBLANK_END in DP mode.
> + * But let's write it anyway to keep the state checker happy.
> + */
> + intel_de_write(dev_priv, TRANS_VBLANK(cpu_transcoder),
> + VBLANK_START(crtc_vblank_start - 1) |
> + VBLANK_END(crtc_vblank_end - 1));
> + /*
> + * The double buffer latch point for TRANS_VTOTAL
> + * is the transcoder's undelayed vblank.
> + */
> + intel_de_write(dev_priv, TRANS_VTOTAL(cpu_transcoder),
> + VACTIVE(crtc_vdisplay - 1) |
> + VTOTAL(crtc_vtotal - 1));
> +}
> +
> static void intel_set_pipe_src_size(const struct intel_crtc_state *crtc_state)
> {
> struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
> @@ -5082,11 +5113,13 @@ intel_pipe_config_compare(const struct intel_crtc_state *current_config,
> PIPE_CONF_CHECK_I(name.crtc_hsync_start); \
> PIPE_CONF_CHECK_I(name.crtc_hsync_end); \
> PIPE_CONF_CHECK_I(name.crtc_vdisplay); \
> - PIPE_CONF_CHECK_I(name.crtc_vtotal); \
> PIPE_CONF_CHECK_I(name.crtc_vblank_start); \
> - PIPE_CONF_CHECK_I(name.crtc_vblank_end); \
> PIPE_CONF_CHECK_I(name.crtc_vsync_start); \
> PIPE_CONF_CHECK_I(name.crtc_vsync_end); \
> + if (!fastset || !pipe_config->update_lrr) { \
> + PIPE_CONF_CHECK_I(name.crtc_vtotal); \
> + PIPE_CONF_CHECK_I(name.crtc_vblank_end); \
> + } \
> } while (0)
>
> #define PIPE_CONF_CHECK_RECT(name) do { \
> @@ -5420,6 +5453,7 @@ int intel_modeset_all_pipes(struct intel_atomic_state *state,
> crtc_state->uapi.mode_changed = true;
> crtc_state->update_pipe = false;
> crtc_state->update_m_n = false;
> + crtc_state->update_lrr = false;
>
> ret = drm_atomic_add_affected_connectors(&state->base,
> &crtc->base);
> @@ -5537,6 +5571,10 @@ static void intel_crtc_check_fastset(const struct intel_crtc_state *old_crtc_sta
> {
> struct drm_i915_private *i915 = to_i915(old_crtc_state->uapi.crtc->dev);
>
> + /* only allow LRR when the timings stay within the VRR range */
> + if (old_crtc_state->vrr.in_range != new_crtc_state->vrr.in_range)
> + new_crtc_state->update_lrr = false;
> +
> if (!intel_pipe_config_compare(old_crtc_state, new_crtc_state, true))
> drm_dbg_kms(&i915->drm, "fastset requirement not met, forcing full modeset\n");
> else
> @@ -5547,6 +5585,11 @@ static void intel_crtc_check_fastset(const struct intel_crtc_state *old_crtc_sta
> &new_crtc_state->dp_m_n))
> new_crtc_state->update_m_n = false;
>
> + if (intel_crtc_needs_modeset(new_crtc_state) ||
> + (old_crtc_state->hw.adjusted_mode.crtc_vtotal == new_crtc_state->hw.adjusted_mode.crtc_vtotal &&
> + old_crtc_state->hw.adjusted_mode.crtc_vblank_end == new_crtc_state->hw.adjusted_mode.crtc_vblank_end))
> + new_crtc_state->update_lrr = false;
> +
> if (!intel_crtc_needs_modeset(new_crtc_state))
> new_crtc_state->update_pipe = true;
> }
> @@ -6262,6 +6305,7 @@ int intel_atomic_check(struct drm_device *dev,
> new_crtc_state->uapi.mode_changed = true;
> new_crtc_state->update_pipe = false;
> new_crtc_state->update_m_n = false;
> + new_crtc_state->update_lrr = false;
> }
> }
>
> @@ -6275,6 +6319,7 @@ int intel_atomic_check(struct drm_device *dev,
> new_crtc_state->uapi.mode_changed = true;
> new_crtc_state->update_pipe = false;
> new_crtc_state->update_m_n = false;
> + new_crtc_state->update_lrr = false;
> }
> }
>
> @@ -6283,6 +6328,7 @@ int intel_atomic_check(struct drm_device *dev,
> new_crtc_state->uapi.mode_changed = true;
> new_crtc_state->update_pipe = false;
> new_crtc_state->update_m_n = false;
> + new_crtc_state->update_lrr = false;
> }
> }
> }
> @@ -6464,6 +6510,9 @@ static void intel_pipe_fastset(const struct intel_crtc_state *old_crtc_state,
> if (new_crtc_state->update_m_n)
> intel_cpu_transcoder_set_m1_n1(crtc, new_crtc_state->cpu_transcoder,
> &new_crtc_state->dp_m_n);
> +
> + if (new_crtc_state->update_lrr)
> + intel_set_transcoder_timings_lrr(new_crtc_state);
> }
>
> static void commit_pipe_pre_planes(struct intel_atomic_state *state,
> @@ -6600,7 +6649,8 @@ static void intel_update_crtc(struct intel_atomic_state *state,
> *
> * FIXME Should be synchronized with the start of vblank somehow...
> */
> - if (vrr_enabling(old_crtc_state, new_crtc_state) || new_crtc_state->update_m_n)
> + if (vrr_enabling(old_crtc_state, new_crtc_state) ||
> + new_crtc_state->update_m_n || new_crtc_state->update_lrr)
> intel_crtc_update_active_timings(new_crtc_state,
> new_crtc_state->vrr.enable);
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display_device.h b/drivers/gpu/drm/i915/display/intel_display_device.h
> index 8198401aa5be..ee77750af82b 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_device.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_device.h
> @@ -56,6 +56,7 @@ struct drm_printer;
> #define HAS_HW_SAGV_WM(i915) (DISPLAY_VER(i915) >= 13 && !IS_DGFX(i915))
> #define HAS_IPC(i915) (DISPLAY_INFO(i915)->has_ipc)
> #define HAS_IPS(i915) (IS_HASWELL_ULT(i915) || IS_BROADWELL(i915))
> +#define HAS_LRR(i915) (DISPLAY_VER(i915) >= 12)
> #define HAS_LSPCON(i915) (IS_DISPLAY_VER(i915, 9, 10))
> #define HAS_MBUS_JOINING(i915) (IS_ALDERLAKE_P(i915) || DISPLAY_VER(i915) >= 14)
> #define HAS_MSO(i915) (DISPLAY_VER(i915) >= 12)
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> index 2f35560d7e4e..536c642eb562 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -1084,6 +1084,7 @@ struct intel_crtc_state {
> unsigned fb_bits; /* framebuffers to flip */
> bool update_pipe; /* can a fast modeset be performed? */
> bool update_m_n; /* update M/N seamlessly during fastset? */
> + bool update_lrr; /* update TRANS_VTOTAL/etc. during fastset? */
> bool disable_cxsr;
> bool update_wm_pre, update_wm_post; /* watermarks are updated */
> bool fifo_changed; /* FIFO split is changed */
> @@ -1383,7 +1384,7 @@ struct intel_crtc_state {
>
> /* Variable Refresh Rate state */
> struct {
> - bool enable;
> + bool enable, in_range;
> u8 pipeline_full;
> u16 flipline, vmin, vmax, guardband;
> } vrr;
> diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
> index 12731ad725a8..5d905f932cb4 100644
> --- a/drivers/gpu/drm/i915/display/intel_vrr.c
> +++ b/drivers/gpu/drm/i915/display/intel_vrr.c
> @@ -120,9 +120,14 @@ intel_vrr_compute_config(struct intel_crtc_state *crtc_state,
> if (adjusted_mode->flags & DRM_MODE_FLAG_INTERLACE)
> return;
>
> - if (!intel_vrr_is_in_range(connector, drm_mode_vrefresh(adjusted_mode)))
> + crtc_state->vrr.in_range =
> + intel_vrr_is_in_range(connector, drm_mode_vrefresh(adjusted_mode));
> + if (!crtc_state->vrr.in_range)
> return;
>
> + if (HAS_LRR(i915))
> + crtc_state->update_lrr = true;
> +
> vmin = DIV_ROUND_UP(adjusted_mode->crtc_clock * 1000,
> adjusted_mode->crtc_htotal * info->monitor_range.max_vfreq);
> vmax = adjusted_mode->crtc_clock * 1000 /
> --
> 2.41.0
>
