[RFC] drm: add support for tiled/compressed/etc modifier in addfb2

[Rob Clark]

On Tue, Dec 16, 2014 at 3:01 AM, Daniel Stone <daniel at fooishbar.org> wrote:
> Hi,
>
> On 16 December 2014 at 03:56, Michel Dänzer <michel at daenzer.net> wrote:
>>
>> On 12.12.2014 20:27, Daniel Stone wrote:
>> > It might be useful to make the interpretation modifiers bitmaskable, so
>> > they can be combined (e.g. wide-range/unclamped YUV | whatever chroma
>> > siting), but I can't think of a usecase for combining multiple layout
>> > modifiers (e.g. this tiling | that compression).
>>
>> I might be misunderstanding what you're referring to, but FWIW: With AMD
>> GPUs, the compression format and tiling parameters can be chosen
>> (mostly) independently.
>
>
> Should've been a little more clear. Definitely each vendor will have their
> own combination of modes, but I mostly meant that I don't really see a use
> for VENDOR_AMD(compression_1) | VENDOR_OTHER(tiling_N), or VENDOR_ARM(afbc)
> | VENDOR_SAMSUNG(tiling_12x64). Each vendor's space would be free to use the
> 24 sub-bits as a bitmask, but I don't think there's a need for combining
> tokens from multiple vendor spaces.
>

fwiw, I bumped it up to 64b (but haven't resent yet).. so now there
are 56bits to divide as vendor sees fit between tiling/compression..
56bits ought to be enough for anyone, right? :-P

BR,
-R

> Cheers,
> Daniel