[Intel-gfx] [PATCH] RFC: drm: add support for tiled/compressed/etc modifier in addfb2

[Tvrtko Ursulin]

On 01/29/2015 05:01 PM, Daniel Vetter wrote:

[snip]

> +
> +/*
> + * Format Modifiers:
> + *
> + * Format modifiers describe, typically, a re-ordering or modification
> + * of the data in a plane of an FB.  This can be used to express tiled/
> + * swizzled formats, or compression, or a combination of the two.
> + *
> + * The upper 8 bits of the format modifier are a vendor-id as assigned
> + * below.  The lower 56 bits are assigned as vendor sees fit.
> + */
> +
> +/* Vendor Ids: */
> +#define DRM_FORMAT_MOD_NONE           0
> +#define DRM_FORMAT_MOD_VENDOR_INTEL   0x01
> +#define DRM_FORMAT_MOD_VENDOR_AMD     0x02
> +#define DRM_FORMAT_MOD_VENDOR_NV      0x03
> +#define DRM_FORMAT_MOD_VENDOR_SAMSUNG 0x04
> +#define DRM_FORMAT_MOD_VENDOR_QCOM    0x05
> +/* add more to the end as needed */
> +
> +#define fourcc_mod_code(vendor, val) \
> +	((((u64)DRM_FORMAT_MOD_VENDOR_## vendor) << 56) | (val & 0x00ffffffffffffffL)
> +
> +/*
> + * Format Modifier tokens:
> + *
> + * When adding a new token please document the layout with a code comment,
> + * similar to the fourcc codes above. drm_fourcc.h is considered the
> + * authoritative source for all of these.
> + */

On one side modifiers are supposed to be opaque, but then this suggest 
they are supposed to be added in this file and described. Is that right?

Regards,

Tvrtko