Re: [PATCH 5/7] drm/i915: Move the dodgy pre-g4x wm stuff into i9xx_wm

["Govindapillai, Vinod" <vinod.govindapillai@intel.com>]

On Mon, 2024-09-16 at 19:24 +0300, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> As with other watermark calculations, the dodgy pre-g4x
> update_wm_{pre,post} flag calcultion would like to know
Typo: calculation
> if a modeset is about to happen or not, and technically
> later stages in the atomic_check() may still flag one.
> In practice that shouldn't happen as we don't have dynamic
> CDCLK implemented for these old platforms.
> 
> Regardless it'll be nice to move this old cruft out from
> the supposedly platform agnostic plane code.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

> ---
>  drivers/gpu/drm/i915/display/i9xx_wm.c        | 74 +++++++++++++++++++
>  .../gpu/drm/i915/display/intel_atomic_plane.c | 36 ---------
>  2 files changed, 74 insertions(+), 36 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/i9xx_wm.c b/drivers/gpu/drm/i915/display/i9xx_wm.c
> index 3151a31a5653..15ed3b810947 100644
> --- a/drivers/gpu/drm/i915/display/i9xx_wm.c
> +++ b/drivers/gpu/drm/i915/display/i9xx_wm.c
> @@ -705,6 +705,76 @@ static void pnv_update_wm(struct drm_i915_private *dev_priv)
>         }
>  }
>  
> +static bool i9xx_wm_need_update(const struct intel_plane_state *old_plane_state,
> +                               const struct intel_plane_state *new_plane_state)
> +{
> +       /* Update watermarks on tiling or size changes. */
> +       if (old_plane_state->uapi.visible != new_plane_state->uapi.visible)
> +               return true;
> +
> +       if (!old_plane_state->hw.fb || !new_plane_state->hw.fb)
> +               return false;
> +
> +       if (old_plane_state->hw.fb->modifier != new_plane_state->hw.fb->modifier ||
> +           old_plane_state->hw.rotation != new_plane_state->hw.rotation ||
> +           drm_rect_width(&old_plane_state->uapi.src) != drm_rect_width(&new_plane_state-
> >uapi.src) ||
> +           drm_rect_height(&old_plane_state->uapi.src) != drm_rect_height(&new_plane_state-
> >uapi.src) ||
> +           drm_rect_width(&old_plane_state->uapi.dst) != drm_rect_width(&new_plane_state-
> >uapi.dst) ||
> +           drm_rect_height(&old_plane_state->uapi.dst) != drm_rect_height(&new_plane_state-
> >uapi.dst))
> +               return true;
> +
> +       return false;
> +}
> +
> +static void i9xx_wm_compute(struct intel_crtc_state *new_crtc_state,
> +                           const struct intel_plane_state *old_plane_state,
> +                           const struct intel_plane_state *new_plane_state)
> +{
> +       bool turn_off, turn_on, visible, was_visible, mode_changed;
> +
> +       mode_changed = intel_crtc_needs_modeset(new_crtc_state);
> +       was_visible = old_plane_state->uapi.visible;
> +       visible = new_plane_state->uapi.visible;
> +
> +       if (!was_visible && !visible)
> +               return;
> +
> +       turn_off = was_visible && (!visible || mode_changed);
> +       turn_on = visible && (!was_visible || mode_changed);
> +
> +       /* FIXME nuke when all wm code is atomic */
> +       if (turn_on) {
> +               new_crtc_state->update_wm_pre = true;
> +       } else if (turn_off) {
> +               new_crtc_state->update_wm_post = true;
> +       } else if (i9xx_wm_need_update(old_plane_state, new_plane_state)) {
> +               /* FIXME bollocks */
> +               new_crtc_state->update_wm_pre = true;
> +               new_crtc_state->update_wm_post = true;
> +       }
> +}
> +
> +static int i9xx_compute_watermarks(struct intel_atomic_state *state,
> +                                  struct intel_crtc *crtc)
> +{
> +       struct intel_crtc_state *new_crtc_state =
> +               intel_atomic_get_new_crtc_state(state, crtc);
> +       const struct intel_plane_state *old_plane_state;
> +       const struct intel_plane_state *new_plane_state;
> +       struct intel_plane *plane;
> +       int i;
> +
> +       for_each_oldnew_intel_plane_in_state(state, plane, old_plane_state,
> +                                            new_plane_state, i) {
> +               if (plane->pipe != crtc->pipe)
> +                       continue;
> +
> +               i9xx_wm_compute(new_crtc_state, old_plane_state, new_plane_state);
> +       }
> +
> +       return 0;
> +}
> +
>  /*
>   * Documentation says:
>   * "If the line size is small, the TLB fetches can get in the way of the
> @@ -4056,18 +4126,22 @@ static const struct intel_wm_funcs g4x_wm_funcs = {
>  };
>  
>  static const struct intel_wm_funcs pnv_wm_funcs = {
> +       .compute_watermarks = i9xx_compute_watermarks,
>         .update_wm = pnv_update_wm,
>  };
>  
>  static const struct intel_wm_funcs i965_wm_funcs = {
> +       .compute_watermarks = i9xx_compute_watermarks,
>         .update_wm = i965_update_wm,
>  };
>  
>  static const struct intel_wm_funcs i9xx_wm_funcs = {
> +       .compute_watermarks = i9xx_compute_watermarks,
>         .update_wm = i9xx_update_wm,
>  };
>  
>  static const struct intel_wm_funcs i845_wm_funcs = {
> +       .compute_watermarks = i9xx_compute_watermarks,
>         .update_wm = i845_update_wm,
>  };
>  
> diff --git a/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> index 2aeb4cd5b5a1..33fec36ec0bd 100644
> --- a/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> +++ b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> @@ -392,28 +392,6 @@ void intel_plane_set_invisible(struct intel_crtc_state *crtc_state,
>         plane_state->uapi.visible = false;
>  }
>  
> -/* FIXME nuke when all wm code is atomic */
> -static bool intel_wm_need_update(const struct intel_plane_state *old_plane_state,
> -                                const struct intel_plane_state *new_plane_state)
> -{
> -       /* Update watermarks on tiling or size changes. */
> -       if (old_plane_state->uapi.visible != new_plane_state->uapi.visible)
> -               return true;
> -
> -       if (!old_plane_state->hw.fb || !new_plane_state->hw.fb)
> -               return false;
> -
> -       if (old_plane_state->hw.fb->modifier != new_plane_state->hw.fb->modifier ||
> -           old_plane_state->hw.rotation != new_plane_state->hw.rotation ||
> -           drm_rect_width(&old_plane_state->uapi.src) != drm_rect_width(&new_plane_state-
> >uapi.src) ||
> -           drm_rect_height(&old_plane_state->uapi.src) != drm_rect_height(&new_plane_state-
> >uapi.src) ||
> -           drm_rect_width(&old_plane_state->uapi.dst) != drm_rect_width(&new_plane_state-
> >uapi.dst) ||
> -           drm_rect_height(&old_plane_state->uapi.dst) != drm_rect_height(&new_plane_state-
> >uapi.dst))
> -               return true;
> -
> -       return false;
> -}
> -
>  static bool intel_plane_is_scaled(const struct intel_plane_state *plane_state)
>  {
>         int src_w = drm_rect_width(&plane_state->uapi.src) >> 16;
> @@ -602,20 +580,6 @@ static int intel_plane_atomic_calc_changes(const struct intel_crtc_state
> *old_cr
>                        was_visible, visible,
>                        turn_off, turn_on, mode_changed);
>  
> -       if (turn_on) {
> -               if (DISPLAY_VER(dev_priv) < 5 && !IS_G4X(dev_priv))
> -                       new_crtc_state->update_wm_pre = true;
> -       } else if (turn_off) {
> -               if (DISPLAY_VER(dev_priv) < 5 && !IS_G4X(dev_priv))
> -                       new_crtc_state->update_wm_post = true;
> -       } else if (intel_wm_need_update(old_plane_state, new_plane_state)) {
> -               if (DISPLAY_VER(dev_priv) < 5 && !IS_G4X(dev_priv)) {
> -                       /* FIXME bollocks */
> -                       new_crtc_state->update_wm_pre = true;
> -                       new_crtc_state->update_wm_post = true;
> -               }
> -       }
> -

With this change, update_wm_pre/post flag will move from intel_atomic_check_planes() to
intel_atomic_check_crtcs() which will call compute_watermarks() and update the flag. Just wanted to
clarify if this is expected.

BR
Vinod


>         if (visible || was_visible)
>                 new_crtc_state->fb_bits |= plane->frontbuffer_bit;
>