On Thu, Mar 24, 2022 at 12:58:32PM +0000, Souza, Jose wrote:
> On Thu, 2022-03-24 at 13:30 +0200, Ville Syrjälä wrote:
> > On Tue, Mar 22, 2022 at 02:46:15PM -0700, José Roberto de Souza wrote:
> > > PIPE_MBUS_DBOX_CTL was only being programmed when a pipe is being
> > > enabled but that could potentially cause issues as it could have
> > > mismatching values while pipes are being enabled.
> > >
> > > So here moving the PIPE_MBUS_DBOX_CTL programming of all pipes to be
> > > executed before the function that enables all pipes, leaving all pipes
> > > with a matching A_CREDIT value.
> > >
> > > While at it, also moving it to intel_pm.c as we are trying to reduce
> > > the gigantic size of it and intel_pm.c have other MBUS programing
> > > sequences.
> > >
> > > v2:
> > > - do not program PIPE_MBUS_DBOX_CTL if pipe will not be active or
> > > when it do not needs modeset
> > > - remove the checks to wait a vblank
> > >
> > > BSpec: 49213
> > > BSpec: 50343
> > > Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> > > Cc: Stanislav Lisovskiy <stanislav.lisovskiy@xxxxxxxxx>
> > > Signed-off-by: José Roberto de Souza <jose.souza@xxxxxxxxx>
> > > ---
> > > drivers/gpu/drm/i915/display/intel_display.c | 37 +--------------
> > > drivers/gpu/drm/i915/intel_pm.c | 47 ++++++++++++++++++++
> > > drivers/gpu/drm/i915/intel_pm.h | 1 +
> > > 3 files changed, 49 insertions(+), 36 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> > > index 424cd7e9afe60..ef5076b5e7027 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_display.c
> > > +++ b/drivers/gpu/drm/i915/display/intel_display.c
> > > @@ -1824,35 +1824,6 @@ static void glk_pipe_scaler_clock_gating_wa(struct drm_i915_private *dev_priv,
> > > intel_de_write(dev_priv, CLKGATE_DIS_PSL(pipe), val);
> > > }
> > >
> > > -static void icl_pipe_mbus_enable(struct intel_crtc *crtc, bool joined_mbus)
> > > -{
> > > - struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
> > > - enum pipe pipe = crtc->pipe;
> > > - u32 val;
> > > -
> > > - val = intel_de_read(dev_priv, PIPE_MBUS_DBOX_CTL(pipe));
> > > - val &= ~MBUS_DBOX_A_CREDIT_MASK;
> > > - /* Wa_22010947358:adl-p */
> > > - if (IS_ALDERLAKE_P(dev_priv))
> > > - val |= joined_mbus ? MBUS_DBOX_A_CREDIT(6) : MBUS_DBOX_A_CREDIT(4);
> > > - else
> > > - val |= MBUS_DBOX_A_CREDIT(2);
> > > -
> > > - val &= ~(MBUS_DBOX_BW_CREDIT_MASK | MBUS_DBOX_B_CREDIT_MASK);
> > > - if (IS_ALDERLAKE_P(dev_priv)) {
> > > - val |= MBUS_DBOX_BW_CREDIT(2);
> > > - val |= MBUS_DBOX_B_CREDIT(8);
> > > - } else if (DISPLAY_VER(dev_priv) >= 12) {
> > > - val |= MBUS_DBOX_BW_CREDIT(2);
> > > - val |= MBUS_DBOX_B_CREDIT(12);
> > > - } else {
> > > - val |= MBUS_DBOX_BW_CREDIT(1);
> > > - val |= MBUS_DBOX_B_CREDIT(8);
> > > - }
> > > -
> > > - intel_de_write(dev_priv, PIPE_MBUS_DBOX_CTL(pipe), val);
> > > -}
> > > -
> > > static void hsw_set_linetime_wm(const struct intel_crtc_state *crtc_state)
> > > {
> > > struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
> > > @@ -1988,13 +1959,6 @@ static void hsw_crtc_enable(struct intel_atomic_state *state,
> > >
> > > intel_initial_watermarks(state, crtc);
> > >
> > > - if (DISPLAY_VER(dev_priv) >= 11) {
> > > - const struct intel_dbuf_state *dbuf_state =
> > > - intel_atomic_get_new_dbuf_state(state);
> > > -
> > > - icl_pipe_mbus_enable(crtc, dbuf_state->joined_mbus);
> > > - }
> > > -
> > > if (intel_crtc_is_bigjoiner_slave(new_crtc_state))
> > > intel_crtc_vblank_on(new_crtc_state);
> > >
> > > @@ -8599,6 +8563,7 @@ static void intel_atomic_commit_tail(struct intel_atomic_state *state)
> > > intel_encoders_update_prepare(state);
> > >
> > > intel_dbuf_pre_plane_update(state);
> > > + intel_mbus_dbox_update(state);
> > >
> > > for_each_new_intel_crtc_in_state(state, crtc, new_crtc_state, i) {
> > > if (new_crtc_state->do_async_flip)
> > > diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> > > index e60c02d760ffa..cf290bb704221 100644
> > > --- a/drivers/gpu/drm/i915/intel_pm.c
> > > +++ b/drivers/gpu/drm/i915/intel_pm.c
> > > @@ -8258,3 +8258,50 @@ void intel_dbuf_post_plane_update(struct intel_atomic_state *state)
> > > gen9_dbuf_slices_update(dev_priv,
> > > new_dbuf_state->enabled_slices);
> > > }
> > > +
> > > +void intel_mbus_dbox_update(struct intel_atomic_state *state)
> > > +{
> > > + struct drm_i915_private *i915 = to_i915(state->base.dev);
> > > + struct intel_crtc_state *new_crtc_state;
> > > + struct intel_dbuf_state *new_dbuf_state;
> > > + struct intel_crtc *crtc;
> > > + int i;
> > > +
> > > + if (DISPLAY_VER(i915) < 11 || !state->modeset)
> > > + return;
> > > +
> > > + if (HAS_MBUS_JOINING(i915))
> > > + new_dbuf_state = intel_atomic_get_dbuf_state(state);
> > > +
> > > + for_each_new_intel_crtc_in_state(state, crtc, new_crtc_state, i) {
> > > + u32 val;
> > > +
> > > + if (!new_crtc_state->hw.active ||
> > > + !intel_crtc_needs_modeset(new_crtc_state))
> > > + continue;
> > > +
> > > + val = intel_de_read(i915, PIPE_MBUS_DBOX_CTL(crtc->pipe));
> > > + val &= ~MBUS_DBOX_A_CREDIT_MASK;
> > > + /* Wa_22010947358:adl-p */
> > > + if (IS_ALDERLAKE_P(i915))
> > > + val |= new_dbuf_state->joined_mbus ? MBUS_DBOX_A_CREDIT(6) :
> > > + MBUS_DBOX_A_CREDIT(4);
> >
> > Hmm. I'm not super happy with the assumption that the dbuf state
> > is there. When reading this it's not immediately obvious why this
> > works.
>
> If there is a modeset it is guarantee that dbuf state will be present in state:
Only if we had some crtcs in the state prior to the ddb computation.
That seems like a very fragile and non-obvious thing to rely on.
I can't even immediately say whether there might already be some way
to get past the ddb calculation w/o any crtcs, and then something else
(cdclk/bw/etc.) adds a bunch of crtcs into the state.
So this kind of magic coupling between the difference states is not
a great idea if the aim is to keep the code obviously correct.
--
Ville Syrjälä
Intel
