On Thu, Sep 14, 2023 at 04:21:18PM -0700, Manasi Navare wrote:
> On Fri, Sep 1, 2023 at 6:05 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
> >
> > 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 ++-
> > drivers/gpu/drm/i915/i915_reg.h | 1 +
> > 7 files changed, 71 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..74cca5af8b4e 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_m_n ||
>
> Did you mean to add new_crtc_state->update_lrr in the condition for
> vrr_enabling ?
Aye. Good catch. Looks like a rebase fail on my part.
>
> > 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_m_n ||
> > 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 /
> > diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> > index e00e4d569ba9..26cc03832f73 100644
> > --- a/drivers/gpu/drm/i915/i915_reg.h
> > +++ b/drivers/gpu/drm/i915/i915_reg.h
> > @@ -5628,6 +5628,7 @@ enum skl_power_gate {
> > #define _TRANS_DDI_FUNC_CTL2_DSI0 0x6b404
> > #define _TRANS_DDI_FUNC_CTL2_DSI1 0x6bc04
> > #define TRANS_DDI_FUNC_CTL2(tran) _MMIO_TRANS2(tran, _TRANS_DDI_FUNC_CTL2_A)
> > +#define DOUBLE_BUFFER_VACTIVE REG_BIT(8) /* tgl+ */
>
> This reg bit is not used anywhere in this patch.
Yeah, originally I thought it might affect this. But I *think* it
actually only affects DSI transcoders. The spec is a bit of a mess
around this stuff tbh.
>
> Regards
> Manasi
>
> > #define PORT_SYNC_MODE_ENABLE REG_BIT(4)
> > #define PORT_SYNC_MODE_MASTER_SELECT_MASK REG_GENMASK(2, 0)
> > #define PORT_SYNC_MODE_MASTER_SELECT(x) REG_FIELD_PREP(PORT_SYNC_MODE_MASTER_SELECT_MASK, (x))
> > --
> > 2.41.0
> >
--
Ville Syrjälä
Intel
