[PATCH v3] drm/i915/display: update handling of FBC when VT-d active workaround

[Hogander, Jouni]

On Tue, 2024-05-28 at 14:48 +0300, Vinod Govindapillai wrote:
> Move the handling of the disabling FBC when VT-d is active wa
> as part of the intel_fbc_check_plane(). As the hw is still there,
> intel_fbc_sanitize should be able to handle the state properly.
> 
> v2: update the patch description (Jani Nikula)
> 
> v3: fix the return value in wa handling (Jani Nikula)
> 
> Bspec: 21664
> Suggested-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Signed-off-by: Vinod Govindapillai <vinod.govindapillai at intel.com>

Reviewed-by: Jouni Högander <jouni.hogander at intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_fbc.c | 22 ++++++----------------
>  1 file changed, 6 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_fbc.c
> b/drivers/gpu/drm/i915/display/intel_fbc.c
> index e9189a864f69..b546ebc6823d 100644
> --- a/drivers/gpu/drm/i915/display/intel_fbc.c
> +++ b/drivers/gpu/drm/i915/display/intel_fbc.c
> @@ -1235,6 +1235,12 @@ static int intel_fbc_check_plane(struct
> intel_atomic_state *state,
>                 return 0;
>         }
>  
> +       /* WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl,bxt */
> +       if (i915_vtd_active(i915) && (IS_SKYLAKE(i915) ||
> IS_BROXTON(i915))) {
> +               plane_state->no_fbc_reason = "VT-d enabled";
> +               return 0;
> +       }
> +
>         crtc_state = intel_atomic_get_new_crtc_state(state, crtc);
>  
>         if (crtc_state->hw.adjusted_mode.flags &
> DRM_MODE_FLAG_INTERLACE) {
> @@ -1820,19 +1826,6 @@ static int intel_sanitize_fbc_option(struct
> drm_i915_private *i915)
>         return 0;
>  }
>  
> -static bool need_fbc_vtd_wa(struct drm_i915_private *i915)
> -{
> -       /* WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl,bxt */
> -       if (i915_vtd_active(i915) &&
> -           (IS_SKYLAKE(i915) || IS_BROXTON(i915))) {
> -               drm_info(&i915->drm,
> -                        "Disabling framebuffer compression (FBC) to
> prevent screen flicker with VT-d enabled\n");
> -               return true;
> -       }
> -
> -       return false;
> -}
> -
>  void intel_fbc_add_plane(struct intel_fbc *fbc, struct intel_plane
> *plane)
>  {
>         plane->fbc = fbc;
> @@ -1878,9 +1871,6 @@ void intel_fbc_init(struct drm_i915_private
> *i915)
>  {
>         enum intel_fbc_id fbc_id;
>  
> -       if (need_fbc_vtd_wa(i915))
> -               DISPLAY_RUNTIME_INFO(i915)->fbc_mask = 0;
> -
>         i915->display.params.enable_fbc =
> intel_sanitize_fbc_option(i915);
>         drm_dbg_kms(&i915->drm, "Sanitized enable_fbc value: %d\n",
>                     i915->display.params.enable_fbc);