Re: [Intel-gfx] [PATCH 2/5] drm/i915/fbc: Split plane stride checks per-platform

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

Hi Ville,


On Thu, 2023-09-14 at 14:38 +0300, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> Carve up stride_is_valid() into per-platform variants to
> make it easier to see what limits are actually being imposed.
> 
> TODO: maybe go for vfuncs later
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_fbc.c | 68 ++++++++++++++++++------
>  1 file changed, 51 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_fbc.c b/drivers/gpu/drm/i915/display/intel_fbc.c
> index 1b3358a0fbfb..4c4626c84666 100644
> --- a/drivers/gpu/drm/i915/display/intel_fbc.c
> +++ b/drivers/gpu/drm/i915/display/intel_fbc.c
> @@ -848,6 +848,47 @@ void intel_fbc_cleanup(struct drm_i915_private *i915)
>         }
>  }
>  
> +static bool i8xx_fbc_stride_is_valid(const struct intel_plane_state *plane_state)
> +{
> +       const struct drm_framebuffer *fb = plane_state->hw.fb;
> +       unsigned int stride = intel_fbc_plane_stride(plane_state) *
> +               fb->format->cpp[0];
> +
> +       return stride == 4096 || stride == 8192;
> +}
> +
> +static bool i965_fbc_stride_is_valid(const struct intel_plane_state *plane_state)
> +{
> +       const struct drm_framebuffer *fb = plane_state->hw.fb;
> +       unsigned int stride = intel_fbc_plane_stride(plane_state) *
> +               fb->format->cpp[0];
> +
> +       return stride >= 2048 && stride <= 16384;
> +}
> +
> +static bool g4x_fbc_stride_is_valid(const struct intel_plane_state *plane_state)
> +{
> +       return true;
> +}
> +
> +static bool skl_fbc_stride_is_valid(const struct intel_plane_state *plane_state)
> +{
> +       const struct drm_framebuffer *fb = plane_state->hw.fb;
> +       unsigned int stride = intel_fbc_plane_stride(plane_state) *
> +               fb->format->cpp[0];
> +
> +       /* Display WA #1105: skl,bxt,kbl,cfl,glk */
> +       if (fb->modifier == DRM_FORMAT_MOD_LINEAR && stride & 511)
> +               return false;
> +
> +       return true;
> +}
> +
> +static bool icl_fbc_stride_is_valid(const struct intel_plane_state *plane_state)
> +{
> +       return true;
> +}
> +
>  static bool stride_is_valid(const struct intel_plane_state *plane_state)
>  {
>         struct drm_i915_private *i915 = to_i915(plane_state->uapi.plane->dev);
> @@ -859,23 +900,16 @@ static bool stride_is_valid(const struct intel_plane_state *plane_state)
>         if (drm_WARN_ON_ONCE(&i915->drm, (stride & (64 - 1)) != 0))
>                 return false;
>  
> -       /* Below are the additional FBC restrictions. */
> -       if (stride < 512)
> -               return false;
Is this check not required anymore for ICL+ and G4x?

> -
> -       if (DISPLAY_VER(i915) == 2 || DISPLAY_VER(i915) == 3)
> -               return stride == 4096 || stride == 8192;
> -
> -       if (DISPLAY_VER(i915) == 4 && !IS_G4X(i915) &&
> -           (stride < 2048 || stride > 16384))
> -               return false;
> -
> -       /* Display WA #1105: skl,bxt,kbl,cfl,glk */
> -       if ((DISPLAY_VER(i915) == 9 || IS_GEMINILAKE(i915)) &&
> -           fb->modifier == DRM_FORMAT_MOD_LINEAR && stride & 511)
> -               return false;
> -
> -       return true;
> +       if (DISPLAY_VER(i915) >= 11)
> +               return icl_fbc_stride_is_valid(plane_state);
> +       else if (DISPLAY_VER(i915) >= 9)
> +               return skl_fbc_stride_is_valid(plane_state);
> +       else if (DISPLAY_VER(i915) >= 5 || IS_G4X(i915))
> +               return g4x_fbc_stride_is_valid(plane_state);
> +       else if (DISPLAY_VER(i915) == 4)
> +               return i965_fbc_stride_is_valid(plane_state);
> +       else
> +               return i8xx_fbc_stride_is_valid(plane_state);
Also I guess we  could pass "stride" as parameter to these functions for clarity and simplify.

There as some IGT CI failures related to bad_stride tests.

BR
Vinod
>  }
>  
>  static bool pixel_format_is_valid(const struct intel_plane_state *plane_state)