Re: [PATCH] drm/tegra: add tiling FB modifiers

[Erik Faye-Lund]

On Tue, Nov 8, 2016 at 8:50 AM, Alexandre Courbot <acourbot@xxxxxxxxxx> wrote:
> Add FB modifiers to allow user-space to specify that a surface is in one
> of the two tiling formats supported by Tegra chips, and add support in
> the tegradrm driver to handle them properly. This is necessary for the
> display controller to directly display buffers generated by the GPU.
>
> This feature is intended to replace the dedicated IOCTL enabled
> by TEGRA_STAGING and to provide a non-staging alternative to that
> solution.
>
> Signed-off-by: Alexandre Courbot <acourbot@xxxxxxxxxx>
> ---
>  drivers/gpu/drm/tegra/drm.c   |  2 ++
>  drivers/gpu/drm/tegra/fb.c    | 23 +++++++++++++++++++---
>  include/uapi/drm/drm_fourcc.h | 45 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 67 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
> index a9630c2d6cb3..36b4b30a5164 100644
> --- a/drivers/gpu/drm/tegra/drm.c
> +++ b/drivers/gpu/drm/tegra/drm.c
> @@ -161,6 +161,8 @@ static int tegra_drm_load(struct drm_device *drm, unsigned long flags)
>         drm->mode_config.max_width = 4096;
>         drm->mode_config.max_height = 4096;
>
> +       drm->mode_config.allow_fb_modifiers = true;
> +
>         drm->mode_config.funcs = &tegra_drm_mode_funcs;
>
>         err = tegra_drm_fb_prepare(drm);
> diff --git a/drivers/gpu/drm/tegra/fb.c b/drivers/gpu/drm/tegra/fb.c
> index e6d71fa4028e..2fded58b2ca5 100644
> --- a/drivers/gpu/drm/tegra/fb.c
> +++ b/drivers/gpu/drm/tegra/fb.c
> @@ -52,9 +52,26 @@ int tegra_fb_get_tiling(struct drm_framebuffer *framebuffer,
>                         struct tegra_bo_tiling *tiling)
>  {
>         struct tegra_fb *fb = to_tegra_fb(framebuffer);
> -
> -       /* TODO: handle YUV formats? */
> -       *tiling = fb->planes[0]->tiling;
> +       uint64_t modifier = fb->base.modifier[0];
> +
> +       switch (fourcc_mod_tegra_mod(modifier)) {
> +       case NV_FORMAT_MOD_TEGRA_TILED:
> +               tiling->mode = TEGRA_BO_TILING_MODE_TILED;
> +               tiling->value = 0;
> +               break;
> +
> +       case NV_FORMAT_MOD_TEGRA_16BX2_BLOCK(0):
> +               tiling->mode = TEGRA_BO_TILING_MODE_BLOCK;
> +               tiling->value = fourcc_mod_tegra_param(modifier);
> +               if (tiling->value > 5)
> +                       return -EINVAL;

Shouldn't this contain some hardware-check for the support? AFAIK, not
all Tegras support all block-heights (if even this mode at all?)...