[Intel-gfx] [PATCH v3 8/8] drm/i915: Bump gen7+ fb size limits to 16kx16k

[Chris Wilson]

Quoting Ville Syrjala (2018-09-25 20:37:14)
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> With gtt remapping in place we can use arbitrarily large
> framebuffers. Let's bump the limits to 16kx16k on gen7+.
> The limit was chosen to match the maximum 2D surface size
> of the 3D engine.
> 
> With the remapping we could easily go higher than that for the
> display engine. However the modesetting ddx will blindly assume
> it can handle whatever is reported via kms. The oversized
> buffer dimensions are not caught by glamor nor Mesa until
> finally an assert will trip when genxml attempts to pack the
> SURFACE_STATE. So we pick a safe limit to avoid the X server
> from crashing (or potentially misbehaving if the genxml asserts
> are compiled out).
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_display.c | 18 ++++++++++++------
>  1 file changed, 12 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index d533a6086169..241b9f6cbb76 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -15524,16 +15524,22 @@ int intel_modeset_init(struct drm_device *dev)
>                 }
>         }
>  
> -       /* maximum framebuffer dimensions */
> -       if (IS_GEN2(dev_priv)) {
> -               dev->mode_config.max_width = 2048;
> -               dev->mode_config.max_height = 2048;
> +       /*
> +        * Maximum framebuffer dimensions, chosen to match
> +        * the maximum render engine surface size on gen4+.
> +        */
> +       if (INTEL_GEN(dev_priv) >= 7) {
> +               dev->mode_config.max_width = 16384;
> +               dev->mode_config.max_height = 16384;
> +       } else if (INTEL_GEN(dev_priv) >= 4) {
> +               dev->mode_config.max_width = 8192;
> +               dev->mode_config.max_height = 8192;
>         } else if (IS_GEN3(dev_priv)) {
>                 dev->mode_config.max_width = 4096;
>                 dev->mode_config.max_height = 4096;

You have the same problem on gen3 then. 3D pipeline is restricted to 2k.
Different rules for different gen. :(
-Chris